If a firm has a near monopoly on an important product (i.e., few substitutes are available), a high level of customer service is not required because a customer who needs the product will buy it under any reasonable customer service standard. As for stage in the PLC, a product just being introduced needs a different kind of service support than one that is in a mature or declining market stage. When introducing a new product, companies want to make sure that there is sufficient supply of it to meet potential customer demand, and so companies might use expedited transportation to protect against out-of-stock situations.