I have a buddy in the industrial tool repair business. When a complaint gets the point of the customer saying his competition would do a better job, my buddy tells the customer to go there instead. That way, my buddy can concentrate on his better customers.

I had an oil well testing business circa 1990. I had one customer that was “high-maintenance”. When we were busy (with good customers), for some reason my equipment was unavailable. But when things were slow, I took on the high-maintenance customer’s work.