filadendron/Getty Images Startup expert Martin Zwilling says only about half of businesses with employees survive at least five years. Entrepreneurs who are too optimistic about their success may overlook failure patterns. They need to test, grow, and revamp their products and services consistently for maximum success. Almost every entrepreneur and new business owner I mentor is certain that his or her idea has a very high probability of success, and all find it hard to believe that only about half of businesses with employees survive at least five years. They always ask me for the key reasons that other people fail, but because I've seen so many different situations, I'm have been reluctant to generalize the failure patterns.