Just In Time" is a process used to eliminate the overstocking of inventory. In order for JIT to really work you need another process called "KanBan". This is a way to tell you when inventory needs to be ordered. I like the two bin system, so as to when I have one bin empty I know its time to order parts from stock to fill the second one, never running out of parts, but also never being overstocked. Inventory buyers have to determine a re-order point on parts based on history usage. The problem here is that if the customer orders above what he usually does, then this could create a shortage of parts . This isn't exactly a bad thing, just creates the need to restudy the history of usage and demand more from the supplier. The quality of parts from supplies also becomes an issue. You can't expect a shipment of parts and out of 1000 you receive only 750 good ones to use. This could keep you from meeting your customer demand.