In the practice of inventory management customer-oriented performance characteristics as opposed to availability-oriented performance characteristics have received more and more attention. Instead of measuring the probability of a stockout one measures the probability that a customer's demand is satisfied within one week. In this paper we derive approximate expressions for the customer waiting time distribution in case a single stockpoint is replenished according to an (s,Q)-policies. The demand process is compound renewal, i.e. customer has a demand distributed according to some arbitrary
distribution funtion. Extensive simulations show that the approximations yield excellent results. The results can be applied to analyze distribution networks where each stockpoint is controlled according to an (s,Q)-model.