How much is one customer worth? How much does it cost to lose one customer? More than you want to know. More than you can measure in real dollars. Most people only measure the dollar loss of a sale, or how much revenue was lost for the year. Big mistake. For openers, multiply that times 20 years. React, Respond, Recover +1 will give you 13.5 Steps To Taking Responsibility When Dealing With Unhappy Or Dissatisfied Customers.