What are the difference between a replenishment philosophy and a requirements philosophy?

There are some differences between a replenishment philosophy and a requirements philosophy: - The requirement philosophy is used in MRP systems whilst the replenishment philosophy is used in order-point systems. - The replenishment philosophy is oriented toward the customer and it more focuses outward objectives where as the requirement philosophy is oriented toward manufacturer and it more focuses inward objectives. - In the replenishment philosophy, material should be replenished when it runs low versus in the requirement philosophy, material is ordered only when a need exists as directed by the master schedule. If there are no manufacturing requirements for a particular part, it will not be replenished, even though the inventory level is low. - In the replenishment philosophy, ABC principle is applied as a control principle and EOQ formula can help providing relative accurate stock level. In the requirement philosophy, ABC principle and the time-honored EOQ do not work well if this order philosophy is applied. - In the requirement philosophy, as MRP is future-oriented so ordering philosophy base on requirement generated from master schedule. In the replenishment philosophy, the forecast of replenishment the stock level base on the past history of demand. - In the replenishment philosophy, if demand is lumpy, materials will be carried on hand during long period of zero demand resulting in unnecessary inventory-carrying cost. But in the requirement philosophy, the requirement of particular part is very important in manufacturing because demand for component parts is lumpy.