Some people live an entire second life, their whole life. Actors in small companies may have 40 hours a week of work outside of their day job, and may keep up this schedule for decades.
I recently did a piece about Sandbox Theatre, a collaborative ensemble theatre in the Twin Cities. It seemed to me an astonishing machine for keeping people creatively alive, long-term -- an opportunity for talented people to participate in every aspect of theatrical production and to explore ideas and images that matter to them at a reasonable pace. Sandbox does one production a year, starting with an idea and a bare outline. All members of the company engage in reflection, research, and creative experimentation, leading up to a show in the Fall.