diff --git a/backend/handlers/bookings/bookings.go b/backend/handlers/bookings/bookings.go
index 610d81a..4b5ea35 100644
--- a/backend/handlers/bookings/bookings.go
+++ b/backend/handlers/bookings/bookings.go
@@ -2698,8 +2698,9 @@ func ProgressBookingHandler(w http.ResponseWriter, r *http.Request) {
 			// Don't award a stamp if this booking already used a loyalty redemption
 			// (take or receive, never both).
 			var loyaltyAppliedOnThisBooking bool
-//nolint:errcheck // zero value is acceptable fallback on scan failure
-			_ = tx.QueryRow(r.Context(), `SELECT EXISTS(SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND discount_source = 'loyalty')`, bookingID).Scan(&loyaltyAppliedOnThisBooking)
+			if err := tx.QueryRow(r.Context(), `SELECT EXISTS(SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND discount_source = 'loyalty')`, bookingID).Scan(&loyaltyAppliedOnThisBooking); err != nil {
+				log.Printf("Failed to check loyalty applied on booking %s: %v", bookingID, err)
+			}
 
 			var newStampCount int
 			if bookingTotal > 0 && !loyaltyAppliedOnThisBooking {
@@ -2735,8 +2736,9 @@ func ProgressBookingHandler(w http.ResponseWriter, r *http.Request) {
 
 			// Skip time-based campaign if already applied at payment time
 			var timeBasedApplied bool
-//nolint:errcheck // zero value is acceptable fallback on scan failure
-			_ = tx.QueryRow(r.Context(), `SELECT EXISTS(SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND discount_source = 'campaign' AND campaign_type = 'time_based')`, bookingID).Scan(&timeBasedApplied)
+			if err := tx.QueryRow(r.Context(), `SELECT EXISTS(SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND discount_source = 'campaign' AND campaign_type = 'time_based')`, bookingID).Scan(&timeBasedApplied); err != nil {
+				log.Printf("Failed to check time-based campaign applied on booking %s: %v", bookingID, err)
+			}
 			if bookingTotal > 0 && !timeBasedApplied {
 				var campaignID string
 				var campaignPercent float64
@@ -2778,13 +2780,14 @@ func ProgressBookingHandler(w http.ResponseWriter, r *http.Request) {
 
 				var milestoneCampaignID string
 				var milestonePercent float64
-//nolint:errcheck // zero value is acceptable fallback on scan failure
-				_ = tx.QueryRow(r.Context(), `
+				if err := tx.QueryRow(r.Context(), `
 				SELECT id, discount_percent FROM discount_campaigns
 				WHERE status = 'active' AND campaign_type = 'milestone' AND milestone_type = 'per_user_booking_count'
 				AND milestone_value = $1
 				AND NOT EXISTS (SELECT 1 FROM booking_discounts WHERE user_id = $2 AND source_id = discount_campaigns.id)
-			`, userBookingCount, booking.User.ID).Scan(&milestoneCampaignID, &milestonePercent)
+			`, userBookingCount, booking.User.ID).Scan(&milestoneCampaignID, &milestonePercent); err != nil {
+					log.Printf("Failed to query per-user milestone campaign for booking %s: %v", bookingID, err)
+				}
 
 				if milestoneCampaignID != "" {
 					discountAmount := roundTo2(bookingTotal * milestonePercent / 100)
@@ -2808,31 +2811,34 @@ func ProgressBookingHandler(w http.ResponseWriter, r *http.Request) {
 				}
 
 				var globalMilestoneApplied bool
-//nolint:errcheck // zero value is acceptable fallback on scan failure
-				_ = tx.QueryRow(r.Context(), `SELECT EXISTS(SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND discount_source = 'campaign' AND campaign_type = 'milestone' AND milestone_type = 'global_booking_count')`, bookingID).Scan(&globalMilestoneApplied)
+				if err := tx.QueryRow(r.Context(), `SELECT EXISTS(SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND discount_source = 'campaign' AND campaign_type = 'milestone' AND milestone_type = 'global_booking_count')`, bookingID).Scan(&globalMilestoneApplied); err != nil {
+					log.Printf("Failed to check global milestone applied on booking %s: %v", bookingID, err)
+				}
 				if !globalMilestoneApplied {
 					var globalCount int
 //nolint:errcheck // zero value is acceptable fallback on scan failure
 					_ = tx.QueryRow(r.Context(), `SELECT COUNT(*) FROM bookings WHERE status = 'completed'`).Scan(&globalCount)
 
-					var hasInPersonPayment bool
-//nolint:errcheck // zero value is acceptable fallback on scan failure
-					_ = tx.QueryRow(r.Context(), `
-					SELECT EXISTS(SELECT 1 FROM payments WHERE booking_id = $1 AND payment_method = 'in_person_card')`, bookingID).Scan(&hasInPersonPayment)
+				var hasInPersonPayment bool
+				if err := tx.QueryRow(r.Context(), `
+				SELECT EXISTS(SELECT 1 FROM payments WHERE booking_id = $1 AND payment_method = 'in_person_card')`, bookingID).Scan(&hasInPersonPayment); err != nil {
+					log.Printf("Failed to check in-person payment on booking %s: %v", bookingID, err)
+				}
 
-					if hasInPersonPayment {
-						var globalCampaignID string
-						var globalPercent float64
-//nolint:errcheck // zero value is acceptable fallback on scan failure
-						_ = tx.QueryRow(r.Context(), `
-						SELECT id, discount_percent FROM discount_campaigns
-						WHERE status = 'active' AND campaign_type = 'milestone' AND milestone_type = 'global_booking_count'
-						AND milestone_value <= $1
-						AND (max_redemptions IS NULL OR times_redeemed < max_redemptions)
-						ORDER BY milestone_value DESC LIMIT 1
-					`, globalCount).Scan(&globalCampaignID, &globalPercent)
+				if hasInPersonPayment {
+					var globalCampaignID string
+					var globalPercent float64
+					if err := tx.QueryRow(r.Context(), `
+					SELECT id, discount_percent FROM discount_campaigns
+					WHERE status = 'active' AND campaign_type = 'milestone' AND milestone_type = 'global_booking_count'
+					AND milestone_value <= $1
+					AND (max_redemptions IS NULL OR times_redeemed < max_redemptions)
+					ORDER BY milestone_value DESC LIMIT 1
+					`, globalCount).Scan(&globalCampaignID, &globalPercent); err != nil {
+						log.Printf("Failed to query global milestone campaign for booking %s: %v", bookingID, err)
+					}
 
-						if globalCampaignID != "" {
+					if globalCampaignID != "" {
 							discountAmount := roundTo2(bookingTotal * globalPercent / 100)
 							if _, err := tx.Exec(r.Context(), `
 							INSERT INTO booking_discounts (booking_id, user_id, discount_source, source_id, campaign_type, milestone_type, discount_percent, original_total, discount_amount)
diff --git a/backend/handlers/bookings/manage.go b/backend/handlers/bookings/manage.go
index d9f9c14..0cb6ae2 100644
--- a/backend/handlers/bookings/manage.go
+++ b/backend/handlers/bookings/manage.go
@@ -283,14 +283,11 @@ func AdminCreateBookingForUserHandler(w http.ResponseWriter, r *http.Request) {
 					}
 				}
 
-				// Get deposit info
-				var depositRequired bool
+				// Get deposit info — deposit_required already fetched above in the main booking query.
 				var preStartPaid float64
-//nolint:errcheck // zero value is acceptable fallback on scan failure
-				_ = db.Conn.QueryRow(r.Context(), `SELECT deposit_required FROM bookings WHERE id = $1`, existingID).Scan(&depositRequired)
-//nolint:errcheck // zero value is acceptable fallback on scan failure
+//nolint:errcheck // zero value is acceptable fallback on scan failure (aggregate with COALESCE)
 				_ = db.Conn.QueryRow(r.Context(), `SELECT COALESCE(SUM(amount), 0) FROM payments WHERE booking_id = $1 AND payment_type IN ('deposit', 'full') AND status = 'completed'`, existingID).Scan(&preStartPaid)
-				populateDepositFields(&existingBooking, depositRequired, preStartPaid)
+				populateDepositFields(&existingBooking, existingBooking.DepositRequired, preStartPaid)
 
 				w.Header().Set("Content-Type", "application/json")
 				w.WriteHeader(http.StatusOK)
@@ -1211,13 +1208,19 @@ func RequestEditHandler(w http.ResponseWriter, r *http.Request) {
 	// Query payment and timing info (used for validation AND auto-approval later)
 	var hasPayments bool
 	hoursUntilCurrent := currentStartTime.Sub(clock.Now()).Hours()
-//nolint:errcheck // zero value is acceptable fallback on scan failure
-	_ = db.Conn.QueryRow(r.Context(), "SELECT EXISTS(SELECT 1 FROM payments WHERE booking_id = $1 AND status = 'completed')", bookingID).Scan(&hasPayments)
+	if err := db.Conn.QueryRow(r.Context(), "SELECT EXISTS(SELECT 1 FROM payments WHERE booking_id = $1 AND status = 'completed')", bookingID).Scan(&hasPayments); err != nil {
+		log.Printf("Failed to check payments for booking %s: %v", bookingID, err)
+		http.Error(w, "Internal server error", http.StatusInternalServerError)
+		return
+	}
 
 	// Check if booking has discounts (affects auto-approval decisions)
 	var hasDiscounts bool
-//nolint:errcheck // zero value is acceptable fallback on scan failure
-	_ = db.Conn.QueryRow(r.Context(), "SELECT EXISTS(SELECT 1 FROM booking_discounts WHERE booking_id = $1)", bookingID).Scan(&hasDiscounts)
+	if err := db.Conn.QueryRow(r.Context(), "SELECT EXISTS(SELECT 1 FROM booking_discounts WHERE booking_id = $1)", bookingID).Scan(&hasDiscounts); err != nil {
+		log.Printf("Failed to check discounts for booking %s: %v", bookingID, err)
+		http.Error(w, "Internal server error", http.StatusInternalServerError)
+		return
+	}
 
 	if req.NewStartTime != nil && !req.NewStartTime.Equal(currentStartTime) {
 		if hasPayments && hoursUntilCurrent < 72 {
@@ -1447,8 +1450,7 @@ func RequestEditHandler(w http.ResponseWriter, r *http.Request) {
 
 		var durationMinutes int
 		if len(req.NewServices) > 0 {
-//nolint:errcheck // zero value is acceptable fallback on scan failure
-			_ = tx.QueryRow(r.Context(), `
+			if err := tx.QueryRow(r.Context(), `
 				SELECT COALESCE(SUM(dur), 60) FROM (
 					SELECT s.duration_minutes AS dur
 					FROM services s
@@ -1458,12 +1460,17 @@ func RequestEditHandler(w http.ResponseWriter, r *http.Request) {
 					FROM custom_services cs
 					WHERE cs.id = ANY($1)
 				) sub
-			`, req.NewServices).Scan(&durationMinutes)
+			`, req.NewServices).Scan(&durationMinutes); err != nil {
+				log.Printf("Failed to calculate duration for edit request %s: %v, using default", bookingID, err)
+				durationMinutes = 60
+			}
 		} else {
-//nolint:errcheck // zero value is acceptable fallback on scan failure
-			_ = tx.QueryRow(r.Context(), `
+			if err := tx.QueryRow(r.Context(), `
 				SELECT total_duration_minutes FROM bookings WHERE id = $1
-			`, bookingID).Scan(&durationMinutes)
+			`, bookingID).Scan(&durationMinutes); err != nil {
+				log.Printf("Failed to get booking duration for edit request %s: %v, using default", bookingID, err)
+				durationMinutes = 60
+			}
 		}
 
 		_, err = tx.Exec(r.Context(), `
diff --git a/backend/handlers/payments/handlers.go b/backend/handlers/payments/handlers.go
index 1cee950..b304f11 100644
--- a/backend/handlers/payments/handlers.go
+++ b/backend/handlers/payments/handlers.go
@@ -141,10 +141,11 @@ func calculateDiscountPreview(ctx context.Context, bookingID string, userID stri
 	}
 
 	var bookingTotal float64
-	//nolint:errcheck // zero value is acceptable fallback on scan failure
-	_ = db.Conn.QueryRow(ctx, `
+	if err := db.Conn.QueryRow(ctx, `
 		SELECT total_amount FROM bookings WHERE id = $1
-	`, bookingID).Scan(&bookingTotal)
+	`, bookingID).Scan(&bookingTotal); err != nil {
+		log.Printf("Failed to query booking total for discount preview %s: %v", bookingID, err)
+	}
 
 	if bookingTotal <= 0 {
 		return resp
@@ -185,13 +186,14 @@ func calculateDiscountPreview(ctx context.Context, bookingID string, userID stri
 	var milestoneCampaignID string
 	var milestonePercent float64
 	var milestoneName string
-	//nolint:errcheck // zero value is acceptable fallback on scan failure
-	_ = db.Conn.QueryRow(ctx, `
+	if err := db.Conn.QueryRow(ctx, `
 		SELECT id, discount_percent, name FROM discount_campaigns
 		WHERE status = 'active' AND campaign_type = 'milestone' AND milestone_type = 'per_user_booking_count'
 		AND milestone_value = $1
 		AND NOT EXISTS (SELECT 1 FROM booking_discounts WHERE user_id = $2 AND source_id = discount_campaigns.id)
-	`, userBookingCount, userID).Scan(&milestoneCampaignID, &milestonePercent, &milestoneName)
+	`, userBookingCount, userID).Scan(&milestoneCampaignID, &milestonePercent, &milestoneName); err != nil {
+		log.Printf("Failed to query milestone campaign for discount preview (user %s, count %d): %v", userID, userBookingCount, err)
+	}
 
 	if milestoneCampaignID != "" {
 		var exists int
@@ -1021,8 +1023,7 @@ func CreateBookingPayment(w http.ResponseWriter, r *http.Request) {
 	// Promote deposit to confirmed if total paid meets the 20% threshold.
 	// Check is inside the transaction so it sees the just-inserted payments.
 	var depositMet bool
-	//nolint:errcheck // zero value is acceptable fallback on scan failure
-	_ = tx.QueryRow(r.Context(), `
+	if err := tx.QueryRow(r.Context(), `
 		WITH booking_total AS (
 			SELECT total_amount * 100 AS total_cents FROM bookings WHERE id = $1
 		),
@@ -1033,7 +1034,9 @@ func CreateBookingPayment(w http.ResponseWriter, r *http.Request) {
 		)
 		SELECT pt.paid_cents >= ROUND(bt.total_cents * 0.2)
 		FROM booking_total bt, paid_total pt
-	`, bookingID).Scan(&depositMet)
+	`, bookingID).Scan(&depositMet); err != nil {
+		log.Printf("Failed to check deposit threshold for booking %s: %v", bookingID, err)
+	}
 
 	if depositMet {
 		if _, err := tx.Exec(r.Context(), `
@@ -1139,13 +1142,14 @@ func applyEligibleCampaignsAtPayment(ctx context.Context, q db.Querier, bookingI
 
 	var milestoneCampaignID string
 	var milestonePercent float64
-	//nolint:errcheck // zero value is acceptable fallback on scan failure
-	_ = q.QueryRow(ctx, `
+	if err := q.QueryRow(ctx, `
 		SELECT id, discount_percent FROM discount_campaigns
 		WHERE status = 'active' AND campaign_type = 'milestone' AND milestone_type = 'per_user_booking_count'
 		AND milestone_value = $1
 		AND NOT EXISTS (SELECT 1 FROM booking_discounts WHERE user_id = $2 AND source_id = discount_campaigns.id)
-	`, userBookingCount, userID).Scan(&milestoneCampaignID, &milestonePercent)
+	`, userBookingCount, userID).Scan(&milestoneCampaignID, &milestonePercent); err != nil {
+		log.Printf("Failed to query per-user milestone campaign: %v", err)
+	}
 
 	if milestoneCampaignID != "" {
 		var exists int
@@ -1251,15 +1255,16 @@ func applyEligibleCampaignsAtPayment(ctx context.Context, q db.Querier, bookingI
 
 		var globalCampaignID string
 		var globalPercent float64
-		//nolint:errcheck // zero value is acceptable fallback on scan failure
-		_ = q.QueryRow(ctx, `
+		if err := q.QueryRow(ctx, `
 			SELECT id, discount_percent FROM discount_campaigns
 			WHERE status = 'active' AND campaign_type = 'milestone' AND milestone_type = 'global_booking_count'
 			AND milestone_value <= $1
 			AND (max_redemptions IS NULL OR times_redeemed < max_redemptions)
 			AND NOT EXISTS (SELECT 1 FROM booking_discounts WHERE source_id = discount_campaigns.id AND booking_id = $2)
 			ORDER BY milestone_value DESC LIMIT 1
-		`, globalCount, bookingID).Scan(&globalCampaignID, &globalPercent)
+		`, globalCount, bookingID).Scan(&globalCampaignID, &globalPercent); err != nil {
+			log.Printf("Failed to query global milestone campaign: %v", err)
+		}
 
 		if globalCampaignID != "" {
 			var exists int