diff --git a/spindle/db/db.go b/spindle/db/db.go
index 4649d6ea9..089ea9fe2 100644
--- a/spindle/db/db.go
+++ b/spindle/db/db.go
@@ -1304,6 +1304,7 @@ func runMigrations(_ context.Context, conn *sql.Conn, logger *slog.Logger) error
 				used integer not null check (used >= 0),
 				primary key (did, resource, period_start)
 			);
+			create index if not exists idx_quota_usage_periods_start on quota_usage_periods(period_start);
 
 			create table if not exists quota_usage_ledger (
 				usage_id text primary key,
diff --git a/spindle/db/quota_minutes.go b/spindle/db/quota_minutes.go
index 57841b93b..1110b749c 100644
--- a/spindle/db/quota_minutes.go
+++ b/spindle/db/quota_minutes.go
@@ -14,10 +14,8 @@ var _ quota.MinutesStore = (*QuotaStore)(nil)
 // 90 days just has to outlast a duplicate finish, not a billing period
 const minutesLedgerRetention = 90 * 24 * time.Hour
 
-func (d *QuotaStore) WithClock(now func() time.Time) *QuotaStore {
-	d.now = now
-	return d
-}
+// a year of history plus the month being read back
+const minutesUsageRetentionMonths = 13
 
 func (d *QuotaStore) CheckMinutes(ctx context.Context, id quota.Identity) error {
 	conn, err := d.db.Conn(ctx)
@@ -80,6 +78,11 @@ func (d *QuotaStore) RecordMinutes(ctx context.Context, usageID string, id quota
 		`, now.Add(-minutesLedgerRetention).Unix()); err != nil {
 			return err
 		}
+		if _, err := conn.ExecContext(ctx, `
+			DELETE FROM quota_usage_periods WHERE period_start < ?
+		`, now.AddDate(0, -minutesUsageRetentionMonths, 0).Unix()); err != nil {
+			return err
+		}
 
 		for _, period := range quota.CIMinutesPeriods {
 			start, _ := period.Window(now)
diff --git a/spindle/db/quota_minutes_test.go b/spindle/db/quota_minutes_test.go
index 1f88b89b8..11bc65490 100644
--- a/spindle/db/quota_minutes_test.go
+++ b/spindle/db/quota_minutes_test.go
@@ -125,7 +125,8 @@ func TestMinutesDeniedOnceTheOwnerIsUsedUpAcrossRepos(t *testing.T) {
 
 func TestMinutesDenialMessageNamesUsageAndReset(t *testing.T) {
 	clock := newTestClock(time.Date(2026, time.October, 17, 12, 0, 0, 0, time.UTC))
-	qs := NewQuotaStore(newTestDB(t), minutesDefaults(3000, 0)).WithClock(clock.Now)
+	qs := NewQuotaStore(newTestDB(t), minutesDefaults(3000, 0))
+	qs.now = clock.Now
 
 	recordMinutes(t, qs, "wf-1", alice1, 3000)
 	got := requireMinutesDenied(t, qs, alice1).Error()
@@ -165,7 +166,8 @@ func TestMinutesOverrideBeatsDefaultAndNullMeansUnlimited(t *testing.T) {
 
 func TestMinutesResetWhenTheMonthRollsOver(t *testing.T) {
 	clock := newTestClock(time.Date(2026, time.October, 31, 23, 59, 0, 0, time.UTC))
-	qs := NewQuotaStore(newTestDB(t), minutesDefaults(10, 0)).WithClock(clock.Now)
+	qs := NewQuotaStore(newTestDB(t), minutesDefaults(10, 0))
+	qs.now = clock.Now
 
 	recordMinutes(t, qs, "wf-1", alice1, 10)
 	requireMinutesDenied(t, qs, alice1)
@@ -225,7 +227,8 @@ func TestMinutesChargeOneRowWhenRepoIsItsOwnOwner(t *testing.T) {
 
 func TestMinutesLedgerIsPruned(t *testing.T) {
 	clock := newTestClock(time.Date(2026, time.January, 1, 0, 0, 0, 0, time.UTC))
-	qs := NewQuotaStore(newTestDB(t), minutesDefaults(0, 0)).WithClock(clock.Now)
+	qs := NewQuotaStore(newTestDB(t), minutesDefaults(0, 0))
+	qs.now = clock.Now
 
 	recordMinutes(t, qs, "old", alice1, 1)
 	clock.Set(clock.Now().Add(minutesLedgerRetention + time.Hour))
@@ -301,3 +304,27 @@ func TestRecoverBillsNothingForOrphanedWorkflows(t *testing.T) {
 		t.Fatalf("usage rows after recovery = %d, %v, want none", n, err)
 	}
 }
+
+func TestMinutesUsageRowsOlderThanThirteenMonthsArePruned(t *testing.T) {
+	clock := newTestClock(time.Date(2025, time.January, 15, 0, 0, 0, 0, time.UTC))
+	qs := NewQuotaStore(newTestDB(t), minutesDefaults(0, 0))
+	qs.now = clock.Now
+
+	recordMinutes(t, qs, "old", alice1, 1)
+	clock.Set(time.Date(2025, time.December, 15, 0, 0, 0, 0, time.UTC))
+	recordMinutes(t, qs, "within-a-year", alice1, 1)
+	var n int
+	if err := qs.db.QueryRow(`SELECT count(*) FROM quota_usage_periods`).Scan(&n); err != nil || n != 4 {
+		t.Fatalf("usage rows after eleven months = %d, %v, want both months kept", n, err)
+	}
+
+	clock.Set(time.Date(2026, time.March, 15, 0, 0, 0, 0, time.UTC))
+	recordMinutes(t, qs, "new", alice1, 1)
+	if err := qs.db.QueryRow(`SELECT count(*) FROM quota_usage_periods WHERE period_start < ?`,
+		time.Date(2025, time.February, 1, 0, 0, 0, 0, time.UTC).Unix()).Scan(&n); err != nil || n != 0 {
+		t.Fatalf("usage rows older than 13 months = %d, %v, want none", n, err)
+	}
+	if err := qs.db.QueryRow(`SELECT count(*) FROM quota_usage_periods`).Scan(&n); err != nil || n != 4 {
+		t.Fatalf("usage rows = %d, %v, want december and march for both scopes", n, err)
+	}
+}