NEW YORK — It's a scary but sometimes necessary way to operate — with only a few clients, and perhaps just one. But what if any of those customers leave in a short time span, erasing a significant chunk of revenue?

Many small business owners have only a handful of customers or clients at a time. If they work solo or have just a few employees, they don't have the bandwith for more work. Similarly, small manufacturers who turn out custom products for other companies or the government may also have few customers.

Owners need to devise strategies to ensure they survive a revenue dip when a customer leaves. Some are always prospecting for new customers, while others who do work for large companies will network their way to contracts with different divisions.