Getting on with your life’s work is used often, which implies a career transition for an individual in whom they exploit their achievements and experiences to date. This is often true of successful entrepreneurs. It is the rare entrepreneur who starts a business as his first job.
The forces driving such transitions come from many sources. In the case of the former athletes or retired military personnel, for example, it was the inevitability of the end of their careers. Others start businesses because they believe in the opportunity represented by a product or an idea. For others, still, unemployment may be a factor which has been and is commonplace during the Bush administration.