private boolean expired() {
    if (orderDate == -1) return false ;
    final int maxTime = World.STANDARD_DAY_LENGTH * 10 ;
    if (actor.world().currentTime() - orderDate > maxTime) return true ;
    final boolean
      ongoing = shop.stocks.specialOrders().includes(order),
      hasItem = shop.stocks.hasItem(item) ;
    if (ongoing || hasItem) return false ;
    return true ;
  }