Complaints come in too late… [I]t will not suffice to have customers that are merely satisfied. Customers that are unhappy and some that are merely satisfied switch. Profit comes from repeat customers—those that boast about the product or service. Quality is already built in before a customer complains. Study of complaints is certainly necessary but it gives a biased picture of performance of a product or of a service. Study of costs of warranty have of course the same deficiency. These principles apply equally well to service and to manufactured product.