diff --git a/src/build_vehicle_gui.cpp b/src/build_vehicle_gui.cpp
index 0dd06a3edb..9279abdbee 100644
--- a/src/build_vehicle_gui.cpp
+++ b/src/build_vehicle_gui.cpp
@@ -967,7 +967,7 @@ int DrawVehiclePurchaseInfo(int left, int right, int y, EngineID engine_number,
 	if (e->type != VEH_TRAIN || e->u.rail.railveh_type != RAILVEH_WAGON) {
 		/* Design date - Life length */
 		SetDParam(0, ymd.year);
-		SetDParam(1, e->GetLifeLengthInDays() / DAYS_IN_LEAP_YEAR);
+		SetDParam(1, DateToYear(e->GetLifeLengthInDays()));
 		DrawString(left, right, y, STR_PURCHASE_INFO_DESIGNED_LIFE);
 		y += FONT_HEIGHT_NORMAL;
 
diff --git a/src/date_type.h b/src/date_type.h
index c88b4f2061..3f69f6050b 100644
--- a/src/date_type.h
+++ b/src/date_type.h
@@ -63,6 +63,16 @@ static constexpr TimerGameCalendar::Date DateAtStartOfYear(TimerGameCalendar::Ye
 	return (DAYS_IN_YEAR * year) + number_of_leap_years;
 }
 
+/**
+ * Calculate the year of a given date.
+ * @param date The date to consider.
+ * @return the year.
+ */
+static inline TimerGameCalendar::Year DateToYear(TimerGameCalendar::Date date)
+{
+	return date / DAYS_IN_LEAP_YEAR;
+}
+
 /**
  * The date of the first day of the original base year.
  */
diff --git a/src/order_cmd.cpp b/src/order_cmd.cpp
index 038f630126..a8f9017e49 100644
--- a/src/order_cmd.cpp
+++ b/src/order_cmd.cpp
@@ -1941,10 +1941,10 @@ VehicleOrderID ProcessConditionalOrder(const Order *order, const Vehicle *v)
 		case OCV_RELIABILITY:        skip_order = OrderConditionCompare(occ, ToPercent16(v->reliability),       value); break;
 		case OCV_MAX_RELIABILITY:    skip_order = OrderConditionCompare(occ, ToPercent16(v->GetEngine()->reliability),   value); break;
 		case OCV_MAX_SPEED:          skip_order = OrderConditionCompare(occ, v->GetDisplayMaxSpeed() * 10 / 16, value); break;
-		case OCV_AGE:                skip_order = OrderConditionCompare(occ, v->age / DAYS_IN_LEAP_YEAR,        value); break;
+		case OCV_AGE:                skip_order = OrderConditionCompare(occ, DateToYear(v->age),                value); break;
 		case OCV_REQUIRES_SERVICE:   skip_order = OrderConditionCompare(occ, v->NeedsServicing(),               value); break;
 		case OCV_UNCONDITIONALLY:    skip_order = true; break;
-		case OCV_REMAINING_LIFETIME: skip_order = OrderConditionCompare(occ, std::max(v->max_age - v->age + DAYS_IN_LEAP_YEAR - 1, 0) / DAYS_IN_LEAP_YEAR, value); break;
+		case OCV_REMAINING_LIFETIME: skip_order = OrderConditionCompare(occ, std::max(DateToYear(v->max_age - v->age + DAYS_IN_LEAP_YEAR - 1), 0), value); break;
 		default: NOT_REACHED();
 	}
 
diff --git a/src/vehicle_gui.cpp b/src/vehicle_gui.cpp
index 607140f31b..5d1a705f3c 100644
--- a/src/vehicle_gui.cpp
+++ b/src/vehicle_gui.cpp
@@ -2495,9 +2495,9 @@ struct VehicleDetailsWindow : Window {
 				Rect tr = r.Shrink(WidgetDimensions::scaled.framerect);
 
 				/* Draw running cost */
-				SetDParam(1, v->age / DAYS_IN_LEAP_YEAR);
+				SetDParam(1, DateToYear(v->age));
 				SetDParam(0, (v->age + DAYS_IN_YEAR < v->max_age) ? STR_VEHICLE_INFO_AGE : STR_VEHICLE_INFO_AGE_RED);
-				SetDParam(2, v->max_age / DAYS_IN_LEAP_YEAR);
+				SetDParam(2, DateToYear(v->max_age));
 				SetDParam(3, v->GetDisplayRunningCost());
 				DrawString(tr, STR_VEHICLE_INFO_AGE_RUNNING_COST_YR);
 				tr.top += FONT_HEIGHT_NORMAL;