diff --git a/cmd/things/add_test.go b/cmd/things/add_test.go
index 1ae3d068..e7ba6166 100644
--- a/cmd/things/add_test.go
+++ b/cmd/things/add_test.go
@@ -1124,7 +1124,7 @@ func TestAddInvalidRefusedBeforeTagsCreated(t *testing.T) {
 // Things understood gives the item a date, which the read-back cannot
 // check, so the add is reported not confirmed (whenPlaced).
 func TestAddWhenPhraseIgnored(t *testing.T) {
-	dated := "start = 1, startDate = " + strconv.Itoa(int(model.ThingsDateFromTime(time.Now().AddDate(0, 0, 3))))
+	dated := "start = 1, startDate = " + strconv.Itoa(int(model.ThingsDateFromTime(time.Now()).AddDays(3)))
 	cases := []struct {
 		name  string
 		extra string
diff --git a/cmd/things/edit_test.go b/cmd/things/edit_test.go
index 4f4d10d3..0f3e46b3 100644
--- a/cmd/things/edit_test.go
+++ b/cmd/things/edit_test.go
@@ -331,7 +331,7 @@ func TestEditCertainNoOpSkipsTheWait(t *testing.T) {
 	deadline := int(model.ThingsDateFromTime(time.Date(2026, 10, 15, 0, 0, 0, 0, time.Local)))
 	day := func(offset int) string { return now.AddDate(0, 0, offset).Format("2006-01-02") }
 	dayInt := func(offset int) string {
-		return strconv.Itoa(int(model.ThingsDateFromTime(now.AddDate(0, 0, offset))))
+		return strconv.Itoa(int(model.ThingsDateFromTime(now).AddDays(offset)))
 	}
 
 	cases := []struct {
@@ -573,6 +573,9 @@ func TestEditReadsTagListOnce(t *testing.T) {
 			t.Fatalf("apply %q: %v", stmt, err)
 		}
 	}
+	if err := rows.Err(); err != nil {
+		t.Fatalf("read schema: %v", err)
+	}
 	_ = rows.Close()
 	fx := dbtest.NewFixture(t, sqlDB)
 	fx.Todo("one-1", "Post letter", 1)
diff --git a/cmd/things/importcreate_test.go b/cmd/things/importcreate_test.go
index 7f32a5cc..4d187b3f 100644
--- a/cmd/things/importcreate_test.go
+++ b/cmd/things/importcreate_test.go
@@ -1238,7 +1238,7 @@ func TestImportNestedInUpdateNotWarned(t *testing.T) {
 func TestImportChecksWhen(t *testing.T) {
 	past := time.Now().AddDate(0, 0, -4).Format("2006-01-02")
 	today := "start = 1, startDate = " + strconv.Itoa(int(model.ThingsDateFromTime(testNow)))
-	tomorrow := "start = 2, startDate = " + strconv.Itoa(int(model.ThingsDateFromTime(testNow.AddDate(0, 0, 1))))
+	tomorrow := "start = 2, startDate = " + strconv.Itoa(int(model.ThingsDateFromTime(testNow).AddDays(1)))
 	for _, tc := range []struct {
 		name    string
 		attrs   string
diff --git a/cmd/things/when_test.go b/cmd/things/when_test.go
index b14e862f..5e4a293c 100644
--- a/cmd/things/when_test.go
+++ b/cmd/things/when_test.go
@@ -68,7 +68,7 @@ func TestPlaceWhen(t *testing.T) {
 func TestWhenUnchangedTime(t *testing.T) {
 	now := time.Date(2026, 10, 7, 15, 0, 0, 0, time.Local)
 	today := model.ThingsDateFromTime(now)
-	tomorrow := model.ThingsDateFromTime(now.AddDate(0, 0, 1))
+	tomorrow := model.ThingsDateFromTime(now).AddDays(1)
 	reminder := func(min int, err error) func() (int, error) { return func() (int, error) { return min, err } }
 	cases := []struct {
 		name     string
@@ -298,7 +298,7 @@ func TestPlaceWhenNearOffsetChange(t *testing.T) {
 func TestEditUnmovedRowAcceptsEitherOutcome(t *testing.T) {
 	now := testNow
 	today := int(model.ThingsDateFromTime(now))
-	old := int(model.ThingsDateFromTime(now.AddDate(0, 0, -3)))
+	old := int(model.ThingsDateFromTime(now).AddDays(-3))
 	past := now.AddDate(0, 0, -1).Format("2006-01-02")
 	type row struct {
 		typ      model.TaskType
@@ -376,7 +376,7 @@ func TestEditUnmovedRowAcceptsEitherOutcome(t *testing.T) {
 func TestEditUnmovedRowWithOtherFieldsNeedsAChange(t *testing.T) {
 	fastVerify(t)
 	database, sqlDB := seedWritable(t)
-	old := int(model.ThingsDateFromTime(testNow.AddDate(0, 0, -3)))
+	old := int(model.ThingsDateFromTime(testNow).AddDays(-3))
 	if _, err := sqlDB.Exec(`UPDATE TMTask SET start = 2, startDate = ?, startBucket = 0 WHERE uuid = 'one-1'`, old); err != nil {
 		t.Fatal(err)
 	}
@@ -399,7 +399,7 @@ func TestEditUnmovedRowWithOtherFieldsNeedsAChange(t *testing.T) {
 // the dropping stub fails it unless the edit skips the read-back wait.
 func TestEditCarriedOverRow(t *testing.T) {
 	today := int(model.ThingsDateFromTime(testNow))
-	yesterday := int(model.ThingsDateFromTime(testNow.AddDate(0, 0, -1)))
+	yesterday := int(model.ThingsDateFromTime(testNow).AddDays(-1))
 	todayDate := testNow.Format("2006-01-02")
 	const reminder = 1207959552
 	seed := func(t *testing.T, sqlDB *sql.DB, start, date, bucket int, reminder any) {
@@ -614,8 +614,8 @@ func TestEditCarriedOverRow(t *testing.T) {
 // part of the day, only for a place that is today.
 func TestWhenPlaceHoldsCarriedOver(t *testing.T) {
 	today := model.ThingsDateFromTime(testNow)
-	yesterday := model.ThingsDateFromTime(testNow.AddDate(0, 0, -1))
-	tomorrow := model.ThingsDateFromTime(testNow.AddDate(0, 0, 1))
+	yesterday := model.ThingsDateFromTime(testNow).AddDays(-1)
+	tomorrow := model.ThingsDateFromTime(testNow).AddDays(1)
 	for _, tc := range []struct {
 		name   string
 		place  whenPlace
@@ -653,7 +653,7 @@ func TestWhenPlaceHoldsCarriedOver(t *testing.T) {
 // certain no-op: --when today on a to-do in the day part with no reminder.
 // The rest are sent and read back.
 func TestWhenUnchangedCarriedOver(t *testing.T) {
-	yesterday := model.ThingsDateFromTime(testNow.AddDate(0, 0, -1))
+	yesterday := model.ThingsDateFromTime(testNow).AddDays(-1)
 	noReminder := func() (int, error) { return reminderNone, nil }
 	at := func(min int) func() (int, error) { return func() (int, error) { return min, nil } }
 	later := testNow.Add(2 * time.Hour)
diff --git a/internal/db/membership_test.go b/internal/db/membership_test.go
index dae6851c..3a0feda6 100644
--- a/internal/db/membership_test.go
+++ b/internal/db/membership_test.go
@@ -23,8 +23,8 @@ func listSet(t *testing.T, d *DB, view string, opts TaskFilter) []string {
 func TestDeadlineProjectInTodayAndUpcoming(t *testing.T) {
 	d, fx := newFixture(t)
 	today := int64(model.ThingsDateFromTime(testNow))
-	earlier := int64(model.ThingsDateFromTime(testNow.AddDate(0, 0, -2)))
-	later := int64(model.ThingsDateFromTime(testNow.AddDate(0, 0, 3)))
+	earlier := int64(model.ThingsDateFromTime(testNow).AddDays(-2))
+	later := int64(model.ThingsDateFromTime(testNow).AddDays(3))
 
 	fx.Project("p-due-today", "Due today", 1, anytime(), deadline(today))
 	fx.Project("p-overdue", "Overdue", 2, anytime(), deadline(earlier))
@@ -54,7 +54,7 @@ func TestDeadlineProjectInTodayAndUpcoming(t *testing.T) {
 func TestSomedayDeadlineInUpcomingAndToday(t *testing.T) {
 	d, fx := newFixture(t)
 	today := int64(model.ThingsDateFromTime(testNow))
-	later := int64(model.ThingsDateFromTime(testNow.AddDate(0, 0, 3)))
+	later := int64(model.ThingsDateFromTime(testNow).AddDays(3))
 
 	fx.Todo("t-someday-later", "Someday to-do due later", 1, someday(), deadline(later))
 	fx.Project("p-someday-later", "Someday project due later", 2, someday(), deadline(later))
@@ -199,7 +199,7 @@ func TestSearchSkipsTrashedProjectChildren(t *testing.T) {
 // untrashedParent. Pinned here so search and the lists cannot drift apart.
 func TestListViewsSkipTrashedProjectChildren(t *testing.T) {
 	d, fx := newFixture(t)
-	later := int64(model.ThingsDateFromTime(testNow.AddDate(0, 0, 3)))
+	later := int64(model.ThingsDateFromTime(testNow).AddDays(3))
 
 	fx.Area("area-work", "Work", 1)
 	fx.Tag("tg-urgent", "urgent", 1)
diff --git a/internal/db/projects.go b/internal/db/projects.go
index 86ae4dc4..c1afb133 100644
--- a/internal/db/projects.go
+++ b/internal/db/projects.go
@@ -9,7 +9,7 @@ import (
 // ListProjects lists the projects, in area order. includeCompleted lists the
 // closed ones too, logged or not. Without it the listing is the open projects
 // and, unless openOnly is set, the ones closed and not yet logged
-// (closedTodayUnlogged), which the app's own project list still holds: on 9
+// (closedUnlogged), which the app's own project list still holds: on 9
 // Oct 2026 AppleScript's `projects` returned a project completed that day
 // that `things projects` left out. That is the rule the task lists follow.
 func (d *DB) ListProjects(areaFilter string, includeCompleted, openOnly bool) ([]model.Project, error) {
diff --git a/internal/db/tasks.go b/internal/db/tasks.go
index 0150ba16..3cee36d7 100644
--- a/internal/db/tasks.go
+++ b/internal/db/tasks.go
@@ -216,9 +216,11 @@ func scanTask(row rowScanner) (model.Task, error) {
 // project, never rows in a list, so they stay out.
 const todoOrProject = "t.type IN (0, 1)"
 
-// closedTodayUnlogged is the app's rule for a closed item Things has not yet filed
-// into the Logbook. Two conditions hold at once, and measuring against the app
-// on 10 Sep 2026 is what established the pair (issue #230).
+// closedUnlogged is the app's rule for a closed item Things has not yet filed
+// into the Logbook, for each choice of its "Move completed items to Logbook"
+// setting (see the end of this comment). Under "daily", two conditions hold
+// at once, and measuring against the app on 10 Sep 2026 is what established
+// the pair (issue #230).
 //
 // The calendar day is the boundary Things actually keeps: the app's Today held
 // six closed items, all closed that day, while its Logbook held forty items
@@ -246,9 +248,9 @@ const todoOrProject = "t.type IN (0, 1)"
 // Now", whatever day it closed. Any other value, or no setting row, keeps the
 // daily rule. The other two were read from the app's preferences, not measured
 // in the live app, as that would mean changing the user's setting.
-var closedTodayUnlogged = closedUnloggedOf("t")
+var closedUnlogged = closedUnloggedOf("t")
 
-// closedUnloggedOf is closedTodayUnlogged asked of the TMTask row aliased
+// closedUnloggedOf is closedUnlogged asked of the TMTask row aliased
 // alias.
 func closedUnloggedOf(alias string) string {
 	stopDate := "COALESCE(" + alias + ".stopDate, 0)"
@@ -336,7 +338,7 @@ const todayDate = "COALESCE(t.startDate, " + thingsToday + ")"
 
 // thingsToday is today's local date in the ThingsDate encoding
 // (year<<16 | month<<12 | day<<7), so it compares directly with startDate and
-// deadline. It comes from today_clock, as closedTodayUnlogged's day does.
+// deadline. It comes from today_clock, as closedUnlogged's daily rule does.
 const thingsToday = `(SELECT day FROM ` + todayClock + `)`
 
 // heldInPlace is the set the Logbook withholds: every closed row Things has
@@ -356,7 +358,7 @@ const thingsToday = `(SELECT day FROM ` + todayClock + `)`
 // withholding such a row would take it out of every list. The Logbook keeps
 // them (includesTemplates) at once. Both halves of notATemplate are "IS NULL"
 // tests, which are never NULL themselves.
-var heldInPlace = "(" + closedTodayUnlogged + " AND " + notATemplate + ")"
+var heldInPlace = "(" + closedUnlogged + " AND " + notATemplate + ")"
 
 // notATemplate excludes the rows those views never carry: the template
 // row itself, and a to-do inside a repeating project template, which carries
@@ -382,7 +384,7 @@ const parentClosed = "COALESCE(p.status, 0) IN (2, 3)"
 // table gives.
 const parentNotClosed = "NOT (" + parentClosed + ")"
 
-// parentCloseUnlogged is closedTodayUnlogged asked of the parent project.
+// parentCloseUnlogged is closedUnlogged asked of the parent project.
 var parentCloseUnlogged = closedUnloggedOf("p")
 
 // parentNotClosedOrUnlogged is the fold the views that show unlogged rows apply:
@@ -444,7 +446,7 @@ func openOrJustClosed(o whereOpts, foldsUnlogged bool) string {
 // projects` and AddTarget all take. fold, when not empty, is a further test
 // on the closed rows alone.
 func openOrUnlogged(fold string) string {
-	closed := closedRows + " AND " + closedTodayUnlogged
+	closed := closedRows + " AND " + closedUnlogged
 	if fold != "" {
 		closed += " AND " + fold
 	}
diff --git a/internal/db/tasks_test.go b/internal/db/tasks_test.go
index a733b06b..849972dd 100644
--- a/internal/db/tasks_test.go
+++ b/internal/db/tasks_test.go
@@ -177,10 +177,10 @@ func TestListTasksTodayCompletedItemFiltering(t *testing.T) {
 	d, fx := newFixture(t)
 	seedTasks(t, d)
 
-	// AddDate keeps the ThingsDate valid across month boundaries; raw bit
+	// AddDays keeps the ThingsDate valid across month boundaries; raw bit
 	// subtraction would underflow the day field to 0 on the 1st.
 	today := int64(model.ThingsDateFromTime(testNow))
-	yesterday := int64(model.ThingsDateFromTime(testNow.AddDate(0, 0, -1)))
+	yesterday := int64(model.ThingsDateFromTime(testNow).AddDays(-1))
 	// Now, not "a minute ago": the calendar day decides membership since issue
 	// #230, and a minute before midnight falls on the previous day. 25 hours
 	// back is safely not today whatever the hour.
@@ -343,7 +343,7 @@ func TestLogbookWithholdsEveryRowClosedToday(t *testing.T) {
 	now := testNow
 	stop := model.TimeToUnix(now)
 	today := int64(model.ThingsDateFromTime(now))
-	later := int64(model.ThingsDateFromTime(now.AddDate(0, 0, 4)))
+	later := int64(model.ThingsDateFromTime(now).AddDays(4))
 
 	cases := []struct {
 		name   string
@@ -444,7 +444,7 @@ func TestLogbookWithholdsEveryRowClosedToday(t *testing.T) {
 // the Logbook or in those lists, never both and never neither.
 func TestClosedTodayOutsideTodayLandsInOneList(t *testing.T) {
 	today := int64(model.ThingsDateFromTime(testNow))
-	future := int64(model.ThingsDateFromTime(testNow.AddDate(0, 0, 3)))
+	future := int64(model.ThingsDateFromTime(testNow).AddDays(3))
 	stopNow := model.TimeToUnix(testNow)
 
 	cases := []struct {
@@ -508,7 +508,7 @@ func TestClosedTodayOutsideTodayLandsInOneList(t *testing.T) {
 // of the day, not under Today and not in the Logbook.
 func TestClosedSuppressedInboxToDoStaysInInbox(t *testing.T) {
 	d, fx := newFixture(t)
-	earlier := int64(model.ThingsDateFromTime(testNow.AddDate(0, 0, -2)))
+	earlier := int64(model.ThingsDateFromTime(testNow).AddDays(-2))
 	fx.Todo("t-closed", "Closed", 1, inbox(), deadline(earlier), suppressed(earlier), completed(model.TimeToUnix(testNow)))
 
 	logged := mustList(t, d, "logbook", TaskFilter{})
@@ -598,9 +598,9 @@ func TestListTasksDateFilters(t *testing.T) {
 	// Upcoming holds only the days after today (issue #363), so the dates
 	// are days to come rather than fixed ones.
 	now := testNow
-	d1 := int64(model.ThingsDateFromTime(now.AddDate(0, 0, 9)))
-	d2 := int64(model.ThingsDateFromTime(now.AddDate(0, 0, 10)))
-	d3 := int64(model.ThingsDateFromTime(now.AddDate(0, 0, 11)))
+	d1 := int64(model.ThingsDateFromTime(now).AddDays(9))
+	d2 := int64(model.ThingsDateFromTime(now).AddDays(10))
+	d3 := int64(model.ThingsDateFromTime(now).AddDays(11))
 
 	fx.Todo("u-09", "Day 9", 1, somedayOn(d1), inArea("a"))
 	fx.Todo("u-10", "Day 10", 2, somedayOn(d2), inArea("a"))
@@ -1400,7 +1400,7 @@ func TestProjectFilterIncludeCompletedKeepsClosedToday(t *testing.T) {
 
 	stopToday := model.TimeToUnix(testNow)
 	stopYesterday := model.TimeToUnix(testNow.Add(-25 * time.Hour))
-	later := int64(model.ThingsDateFromTime(testNow.AddDate(0, 0, 2)))
+	later := int64(model.ThingsDateFromTime(testNow).AddDays(2))
 	fx.Project("proj-open", "Live", 1)
 	fx.Heading("head", "Phase 1", 2, inProject("proj-open"))
 
@@ -1441,7 +1441,7 @@ func TestAreaFilterIncludeCompletedKeepsClosedToday(t *testing.T) {
 
 	stopToday := model.TimeToUnix(testNow)
 	stopYesterday := model.TimeToUnix(testNow.Add(-25 * time.Hour))
-	later := int64(model.ThingsDateFromTime(testNow.AddDate(0, 0, 2)))
+	later := int64(model.ThingsDateFromTime(testNow).AddDays(2))
 	fx.Area("ar", "Work", 1)
 	fx.Project("proj-open", "Live", 1, inArea("ar"))
 	fx.Project("proj-done", "Shipped", 2, inArea("ar"), completed(stopToday))
@@ -1535,8 +1535,8 @@ func TestListTasksProjectOrderMatchesProjectPage(t *testing.T) {
 	d, fx := newFixture(t)
 	now := testNow
 	today := int64(model.ThingsDateFromTime(now))
-	sooner := int64(model.ThingsDateFromTime(now.AddDate(0, 0, 7)))
-	later := int64(model.ThingsDateFromTime(now.AddDate(0, 0, 17)))
+	sooner := int64(model.ThingsDateFromTime(now).AddDays(7))
+	later := int64(model.ThingsDateFromTime(now).AddDays(17))
 
 	fx.Project("proj", "Ship v2", 1)
 	fx.Heading("head-1", "Phase one", -357, inProject("proj"))
@@ -2221,7 +2221,7 @@ func TestAnytimeLeavesOutToDosInDeferredProjects(t *testing.T) {
 
 	now := testNow
 	today := int64(model.ThingsDateFromTime(now))
-	later := int64(model.ThingsDateFromTime(now.AddDate(0, 0, 7)))
+	later := int64(model.ThingsDateFromTime(now).AddDays(7))
 
 	fx.Project("proj-someday", "Someday project", 1, someday())
 	fx.Project("proj-scheduled", "Scheduled project", 2, somedayOn(later))
@@ -2258,7 +2258,7 @@ func TestAnytimeLeavesOutToDosInDeferredProjects(t *testing.T) {
 // day (issue #238).
 func TestClosedTodayInDeferredProjectLandsInOneList(t *testing.T) {
 	now := testNow
-	later := int64(model.ThingsDateFromTime(now.AddDate(0, 0, 7)))
+	later := int64(model.ThingsDateFromTime(now).AddDays(7))
 	stop := model.TimeToUnix(now)
 
 	cases := []struct {
@@ -2405,9 +2405,9 @@ func TestUpcomingListsAnytimeToDosDueLater(t *testing.T) {
 
 	now := testNow
 	today := int64(model.ThingsDateFromTime(now))
-	tomorrow := int64(model.ThingsDateFromTime(now.AddDate(0, 0, 1)))
-	later := int64(model.ThingsDateFromTime(now.AddDate(0, 0, 3)))
-	yesterday := int64(model.ThingsDateFromTime(now.AddDate(0, 0, -1)))
+	tomorrow := int64(model.ThingsDateFromTime(now).AddDays(1))
+	later := int64(model.ThingsDateFromTime(now).AddDays(3))
+	yesterday := int64(model.ThingsDateFromTime(now).AddDays(-1))
 
 	fx.Todo("sched-tomorrow", "Scheduled tomorrow", 1, somedayOn(tomorrow), todayIndex(-100))
 	fx.Todo("due-tomorrow", "Due tomorrow", 2, anytime(), deadline(tomorrow), todayIndex(-500))
@@ -2441,8 +2441,8 @@ func TestTodayListsUndatedToDosDueOrOverdue(t *testing.T) {
 
 	now := testNow
 	today := int64(model.ThingsDateFromTime(now))
-	tomorrow := int64(model.ThingsDateFromTime(now.AddDate(0, 0, 1)))
-	earlier := int64(model.ThingsDateFromTime(now.AddDate(0, 0, -2)))
+	tomorrow := int64(model.ThingsDateFromTime(now).AddDays(1))
+	earlier := int64(model.ThingsDateFromTime(now).AddDays(-2))
 
 	fx.Todo("sched-today", "Scheduled today", 1, anytimeOn(today))
 	fx.Todo("anytime-due-today", "Anytime due today", 2, anytime(), deadline(today))
@@ -2468,7 +2468,7 @@ func TestTodayListsUndatedToDosDueOrOverdue(t *testing.T) {
 	on := model.ThingsDate(today)
 	got = mustList(t, d, "today", TaskFilter{On: &on})
 	assertSet(t, got, want, "today --on today")
-	from := model.ThingsDate(int64(model.ThingsDateFromTime(now.AddDate(0, 0, -1))))
+	from := model.ThingsDate(int64(model.ThingsDateFromTime(now).AddDays(-1)))
 	got = mustList(t, d, "today", TaskFilter{From: &from})
 	assertSet(t, got, want, "today --from yesterday")
 }
@@ -2484,8 +2484,8 @@ func TestScheduledRowNotYetMovedIsToday(t *testing.T) {
 
 	now := testNow
 	today := int64(model.ThingsDateFromTime(now))
-	yesterday := int64(model.ThingsDateFromTime(now.AddDate(0, 0, -1)))
-	tomorrow := int64(model.ThingsDateFromTime(now.AddDate(0, 0, 1)))
+	yesterday := int64(model.ThingsDateFromTime(now).AddDays(-1))
+	tomorrow := int64(model.ThingsDateFromTime(now).AddDays(1))
 
 	fx.Todo("stuck-today", "Scheduled today, not yet moved", 1, somedayOn(today))
 	fx.Todo("stuck-yesterday", "Scheduled yesterday, not yet moved", 2, somedayOn(yesterday))
@@ -2529,7 +2529,7 @@ func TestScheduledRowNotYetMovedReportsAnytime(t *testing.T) {
 
 	now := testNow
 	today := int64(model.ThingsDateFromTime(now))
-	tomorrow := int64(model.ThingsDateFromTime(now.AddDate(0, 0, 1)))
+	tomorrow := int64(model.ThingsDateFromTime(now).AddDays(1))
 	done := float64(now.Unix())
 
 	fx.Todo("stuck-today", "Scheduled today, not yet moved", 1, somedayOn(today))
@@ -2593,7 +2593,7 @@ func TestAnytimeKeepsToDosOfProjectNotYetMoved(t *testing.T) {
 
 	now := testNow
 	today := int64(model.ThingsDateFromTime(now))
-	tomorrow := int64(model.ThingsDateFromTime(now.AddDate(0, 0, 1)))
+	tomorrow := int64(model.ThingsDateFromTime(now).AddDays(1))
 
 	fx.Project("proj-stuck", "Project scheduled today, not yet moved", 1, somedayOn(today))
 	fx.Project("proj-tomorrow", "Project scheduled tomorrow", 2, somedayOn(tomorrow))
@@ -2614,7 +2614,7 @@ func TestProjectPageOrdersNotYetMovedRowAsToday(t *testing.T) {
 
 	now := testNow
 	today := int64(model.ThingsDateFromTime(now))
-	tomorrow := int64(model.ThingsDateFromTime(now.AddDate(0, 0, 1)))
+	tomorrow := int64(model.ThingsDateFromTime(now).AddDays(1))
 
 	fx.Project("proj", "Project", 1, anytime())
 	fx.Todo("sched-tomorrow", "Scheduled tomorrow", 1, somedayOn(tomorrow), inProject("proj"))
@@ -2635,8 +2635,8 @@ func TestInboxLeavesOutToDosTodayHolds(t *testing.T) {
 
 	now := testNow
 	today := int64(model.ThingsDateFromTime(now))
-	tomorrow := int64(model.ThingsDateFromTime(now.AddDate(0, 0, 1)))
-	earlier := int64(model.ThingsDateFromTime(now.AddDate(0, 0, -2)))
+	tomorrow := int64(model.ThingsDateFromTime(now).AddDays(1))
+	earlier := int64(model.ThingsDateFromTime(now).AddDays(-2))
 
 	fx.Todo("inbox-plain", "Inbox plain", 1, inbox())
 	fx.Todo("inbox-due-today", "Inbox due today", 2, inbox(), deadline(today))
@@ -2665,8 +2665,8 @@ func TestAnytimeListsInboxToDosTodayHolds(t *testing.T) {
 
 	now := testNow
 	today := int64(model.ThingsDateFromTime(now))
-	tomorrow := int64(model.ThingsDateFromTime(now.AddDate(0, 0, 1)))
-	earlier := int64(model.ThingsDateFromTime(now.AddDate(0, 0, -2)))
+	tomorrow := int64(model.ThingsDateFromTime(now).AddDays(1))
+	earlier := int64(model.ThingsDateFromTime(now).AddDays(-2))
 
 	fx.Todo("inbox-plain", "Inbox plain", 1, inbox())
 	fx.Todo("inbox-due-today", "Inbox due today", 2, inbox(), deadline(today))
@@ -2874,8 +2874,8 @@ func TestTodayOrdersByReferenceDateThenTodayIndex(t *testing.T) {
 	d, fx := newFixture(t)
 
 	today := int64(model.ThingsDateFromTime(testNow))
-	yesterday := int64(model.ThingsDateFromTime(testNow.AddDate(0, 0, -1)))
-	earlier := int64(model.ThingsDateFromTime(testNow.AddDate(0, 0, -3)))
+	yesterday := int64(model.ThingsDateFromTime(testNow).AddDays(-1))
+	earlier := int64(model.ThingsDateFromTime(testNow).AddDays(-3))
 	stop := model.TimeToUnix(testNow)
 	fx.Todo("old-first", "One", 1, anytimeOn(today), todayIndex(-900), todayIndexRef(earlier))
 	fx.Todo("new-second", "Two", 2, anytimeOn(today), todayIndex(-100), todayIndexRef(today))
@@ -2928,7 +2928,7 @@ func TestUpcomingIncludeCompleted(t *testing.T) {
 
 	stopToday := model.TimeToUnix(testNow)
 	stopYesterday := model.TimeToUnix(testNow.Add(-25 * time.Hour))
-	later := int64(model.ThingsDateFromTime(testNow.AddDate(0, 0, 2)))
+	later := int64(model.ThingsDateFromTime(testNow).AddDays(2))
 
 	fx.Todo("open-later", "Open", 1, somedayOn(later))
 	fx.Todo("done-ahead", "Done ahead", 2, somedayOn(later), completed(stopToday))
diff --git a/internal/db/view_order_test.go b/internal/db/view_order_test.go
index 6ef887d1..92ab9e17 100644
--- a/internal/db/view_order_test.go
+++ b/internal/db/view_order_test.go
@@ -35,8 +35,8 @@ func TestTodayListsEveningRowsLast(t *testing.T) {
 func TestTodayOrdersProjectGroupsBySchedule(t *testing.T) {
 	d, fx := newFixture(t)
 	today := int64(model.ThingsDateFromTime(testNow))
-	soon := int64(model.ThingsDateFromTime(testNow.AddDate(0, 0, 3)))
-	later := int64(model.ThingsDateFromTime(testNow.AddDate(0, 0, 6)))
+	soon := int64(model.ThingsDateFromTime(testNow).AddDays(3))
+	later := int64(model.ThingsDateFromTime(testNow).AddDays(6))
 
 	fx.Project("p-someday-b", "Someday B", 0, someday())
 	fx.Project("p-later", "Later", 0, somedayOn(later))
@@ -103,8 +103,8 @@ func TestSomedayListsProjectRowsFirst(t *testing.T) {
 // CLI keeps them after the loose ones, the order Anytime uses.
 func TestAreaListingOrdersProjectsThenLooseThenChildren(t *testing.T) {
 	d, fx := newFixture(t)
-	soon := int64(model.ThingsDateFromTime(testNow.AddDate(0, 0, 3)))
-	later := int64(model.ThingsDateFromTime(testNow.AddDate(0, 0, 6)))
+	soon := int64(model.ThingsDateFromTime(testNow).AddDays(3))
+	later := int64(model.ThingsDateFromTime(testNow).AddDays(6))
 	fx.Area("ar", "Personal", -3070)
 
 	fx.Project("p1", "P1", -4767, anytime(), inArea("ar"))
diff --git a/tools/compare/run.sh b/tools/compare/run.sh
new file mode 100755
index 00000000..fc749d0d
--- /dev/null
+++ b/tools/compare/run.sh
@@ -0,0 +1,76 @@
+#!/bin/bash
+# Compare two things binaries on the same input, to check a change keeps
+# behaviour. Each binary runs against its own fresh copy of a seeded test
+# database, with `open` and `osascript` replaced by shims that only log
+# (nothing reaches the Things app). The script then diffs stdout, stderr,
+# the exit code, the shim log and the task statuses left in the database.
+#
+# Usage:
+#   OLD=path/to/things-old NEW=path/to/things-new tools/compare/run.sh NAME STDIN ARGS...
+#
+#   NAME   a label for this case; outputs go to $OUT/NAME.old and $OUT/NAME.new
+#   STDIN  a file to feed on stdin, or - for none
+#   ARGS   the things command line, e.g. show TODO1
+#
+# Example:
+#   git worktree add /tmp/things-main origin/main
+#   (cd /tmp/things-main && go build -o /tmp/things-old ./cmd/things)
+#   go build -o /tmp/things-new ./cmd/things
+#   OLD=/tmp/things-old NEW=/tmp/things-new tools/compare/run.sh show-1 - show TODO1
+#
+# Prints "SAME NAME (exit N, shim N)", or "DIFF NAME" and the first lines of
+# the diff and exits 1. Set SHIMAPPLY=1 for the osascript shim to apply
+# complete and cancel to the database copy, so a read-back can see them. The database is
+# built from internal/db/dbtest/schema.sql and tools/compare/seed.sql. OUT
+# defaults to a fresh temporary directory.
+#
+# A refusal that only the new binary makes means the old one writes: compare
+# only inputs both refuse, or use the test stubs.
+set -u
+here=$(cd "$(dirname "$0")" && pwd)
+root=$(cd "$here/../.." && pwd)
+: "${OLD:?set OLD to the old things binary}"
+: "${NEW:?set NEW to the new things binary}"
+OUT=${OUT:-$(mktemp -d)}
+mkdir -p "$OUT"
+[ $# -ge 2 ] || { echo "usage: OLD=... NEW=... $0 NAME STDIN|- ARGS..." >&2; exit 2; }
+name=$1; shift; in=$1; shift
+
+# Resolve both binaries now: under env -i PATH is the shim directory, so a
+# bare name would not be found and both runs would fail alike as "SAME".
+OLD=$(command -v "$OLD") || { echo "OLD not found" >&2; exit 2; }
+NEW=$(command -v "$NEW") || { echo "NEW not found" >&2; exit 2; }
+case $OLD in /*) ;; *) OLD=$PWD/$OLD;; esac
+case $NEW in /*) ;; *) NEW=$PWD/$NEW;; esac
+
+# Built under a temporary name and moved into place, so a failed seed never
+# leaves a half-built base for the next case to reuse.
+base=$OUT/base.sqlite
+if [ ! -f "$base" ]; then
+  rm -f "$base.tmp"
+  if ! /usr/bin/sqlite3 "$base.tmp" < "$root/internal/db/dbtest/schema.sql" ||
+    ! /usr/bin/sqlite3 "$base.tmp" < "$here/seed.sql"; then
+    rm -f "$base.tmp"; exit 1
+  fi
+  mv "$base.tmp" "$base"
+fi
+
+for v in old new; do
+  bin=$OLD; [ $v = new ] && bin=$NEW
+  d=$OUT/$name.$v; rm -rf "$d"; mkdir -p "$d/home"
+  cp "$base" "$d/db.sqlite"
+  : > "$d/shim.log"
+  if [ "$in" = "-" ]; then inf=/dev/null; else inf=$in; fi
+  env -i HOME="$d/home" XDG_CONFIG_HOME="$d/home/.config" PATH="$here/shim" \
+    SHIMLOG="$d/shim.log" SHIMDB="$d/db.sqlite" SHIMAPPLY="${SHIMAPPLY:-}" TZ=Europe/London \
+    "$bin" --db "$d/db.sqlite" --color never --verify-timeout 600ms "$@" <"$inf" >"$d/stdout" 2>"$d/stderr"
+  echo $? > "$d/exit"
+  sed -i '' "s#$d#<D>#g" "$d/stdout" "$d/stderr" "$d/shim.log"
+  /usr/bin/sqlite3 "$d/db.sqlite" "select uuid,status,stopDate from TMTask order by uuid" > "$d/dbstate"
+done
+if diff -r -x db.sqlite -x home "$OUT/$name.old" "$OUT/$name.new" >/dev/null; then
+  echo "SAME $name (exit $(cat "$OUT/$name.new/exit"), shim $(wc -l < "$OUT/$name.new/shim.log" | tr -d ' '))"
+else
+  echo "DIFF $name"; diff -r -x db.sqlite -x home "$OUT/$name.old" "$OUT/$name.new" | head -30
+  exit 1
+fi
diff --git a/tools/compare/seed.sql b/tools/compare/seed.sql
new file mode 100644
index 00000000..b03f4cf4
--- /dev/null
+++ b/tools/compare/seed.sql
@@ -0,0 +1,22 @@
+-- Test data for tools/compare/run.sh, applied over internal/db/dbtest/schema.sql.
+INSERT INTO TMSettings VALUES ('s','tok123',1,NULL);
+INSERT INTO TMArea VALUES ('AREA1','Work',1,1);
+INSERT INTO TMTag VALUES ('TAG1','urgent',NULL,NULL,1);
+-- project open, project done
+INSERT INTO TMTask (uuid,title,notes,type,status,creationDate,userModificationDate,trashed,start,startBucket,"index",area,untrashedLeafActionsCount,openUntrashedLeafActionsCount) VALUES
+ ('PROJ1','Alpha project','',1,0,1760000000,1760000000,0,1,0,1,'AREA1',2,1),
+ ('PROJ2','Beta project','',1,3,1760000000,1760000000,0,1,0,2,NULL,0,0);
+INSERT INTO TMTask (uuid,title,notes,type,status,creationDate,userModificationDate,trashed,start,startBucket,"index",project) VALUES
+ ('HEAD1','Phase one','',2,0,1760000000,1760000000,0,1,0,1,'PROJ1');
+INSERT INTO TMTask (uuid,title,notes,type,status,stopDate,creationDate,userModificationDate,trashed,start,startBucket,startDate,deadline,"index",todayIndex,area,project,heading,rt1_recurrenceRule) VALUES
+ ('TODO1','Buy milk','some notes',0,0,NULL,1760000000,1760000000,0,1,0,132818176,NULL,1,1,NULL,NULL,NULL,NULL),
+ ('TODO2','Write report','',0,0,NULL,1760000000,1760000000,0,1,0,NULL,132818304,2,0,NULL,'PROJ1','HEAD1',NULL),
+ ('TODO3','Done thing','',0,3,1760090000,1760000000,1760000000,0,1,0,NULL,NULL,3,0,NULL,NULL,NULL,NULL),
+ ('TODO4','Cancelled thing','',0,2,1760090000,1760000000,1760000000,0,1,0,NULL,NULL,4,0,NULL,NULL,NULL,NULL),
+ ('TODO5','Repeat thing','',0,0,NULL,1760000000,1760000000,0,1,0,NULL,NULL,5,0,NULL,NULL,NULL,x'00'),
+ ('TODO6','Trashed thing','',0,0,NULL,1760000000,1760000000,1,1,0,NULL,NULL,6,0,NULL,NULL,NULL,NULL),
+ ('TODO7','Inbox item','',0,0,NULL,1760000000,1760000000,0,0,0,NULL,NULL,7,0,NULL,NULL,NULL,NULL),
+ ('TODO8','Someday item','',0,0,NULL,1760000000,1760000000,0,2,0,NULL,NULL,8,0,'AREA1',NULL,NULL,NULL),
+ ('TODO9','Buy milk','dup title',0,0,NULL,1760000000,1760000000,0,1,0,NULL,NULL,9,0,NULL,NULL,NULL,NULL);
+INSERT INTO TMTaskTag VALUES ('TODO1','TAG1');
+INSERT INTO TMChecklistItem VALUES ('CL1','eggs',0,NULL,1,'TODO1'),('CL2','bread',3,1760090000,2,'TODO1');
diff --git a/tools/compare/shim/open b/tools/compare/shim/open
new file mode 100755
index 00000000..5ba68ae5
--- /dev/null
+++ b/tools/compare/shim/open
@@ -0,0 +1,3 @@
+#!/bin/sh
+echo "open $*" >> "$SHIMLOG"
+exit 0
diff --git a/tools/compare/shim/osascript b/tools/compare/shim/osascript
new file mode 100755
index 00000000..1f81aa04
--- /dev/null
+++ b/tools/compare/shim/osascript
@@ -0,0 +1,11 @@
+#!/bin/sh
+printf 'osascript %s\n' "$*" >> "$SHIMLOG"
+if [ -n "$SHIMAPPLY" ]; then
+  id=$(printf '%s' "$2" | /usr/bin/sed -n 's/.* id "\([^"]*\)".*/\1/p')
+  case "$2" in *"to completed"*) st=3;; *"to canceled"*) st=2;; *) exit 0;; esac
+  # Today's local midnight: a close the app would still hold unlogged, and
+  # the same value for both runs of a case.
+  stop=$(/bin/date -j -v0H -v0M -v0S +%s)
+  /usr/bin/sqlite3 "$SHIMDB" "UPDATE TMTask SET status=$st, stopDate=$stop, userModificationDate=$((stop + 1)) WHERE uuid='$id';"
+fi
+exit 0