just in time - A Balanced View
In spite of the enormous advantage attributed to just in time, most of its adopters embrace it only partially. Many companies that are considered users of just in time purchasing handle only a small percentage of their materials requirements by just in time methods. Among the reasons are (1) the time and effort required to convert many suppliers to a just in time shipping pattern, (2) the difficulty of obtaining shipping at a cost low enough to justify many small deliveries, (3) the likelihood of occasional shipping delays if suppliers are hundreds of miles away, and (4) the frustrating tendency for a low-cost, allegedly noncritical part to become critical when it does not arrive on time and an important customer's order cannot be finished because there is no safety stock. For these and other reasons, some companies claim to have adopted just in time but continue to keep safety stocks of many materials “just in case.”