When film directors who aren't rich have long breaks between making films, how do they make money/pay the bills?

I've always wondered that if a filmmaker (and lets narrow this discussion to Hollywood for now, for the sake of this discussion) makes one film every few years, i.e not a stable and regular income, how do they pay the bills in the interim when it doesn't seem like they're doing other film related activity (producing, writing, other crew work)?

Obviously someone like James Cameron has so much money that he could take huge breaks in between movies, but what about more second/third tier directors who might make one film every 5 years or something?

Obviously everyone will have their own story of what they do, but does anyone know what such people do who are obviously very specialised and advanced in a certain field (they don't let just anyone direct a big budget movie)?