I think the "fail early" advice is applicable here. I left my (quite rewarding) job of 3 years to travel and it was a very difficult decision. In retrospect I

I think the "fail early" advice is applicable here. I left my (quite rewarding) job of 3 years to travel and it was a very difficult decision. In retrospect I should have left much earlier, but instead I waited until I owned several big projects. I quit a few months after receiving their "employee of the quarter" award, still feeling pretty guilty about that one. If it's obvious that the situation isn't sustainable and that you'll have to leave sooner or later, sooner is preferable from all sides.