A Google search of the phrase “new customers only” reveals more than 3 million web pages. Radio ads for what look like exceptional deals often include the modifier, “new customers only;” existing customers are not eligible. We therefore advise our readers to always be new customers despite the cost to the sellers.

It is a general rule of thumb that it costs about seven times as much to get a new customer as it does to keep an existing one. Most profits also come from long-term relationships. “When I see a frown on a customer’s face, I see $50,000 about to walk out the door,” said grocer Stew Leonard to business writer Tom Peters in Thriving on Chaos  (Harper & Row, 1987). That’s because a customer who spends $100 a week on groceries will spend more than $50,000 in 10 years.

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