I prefer a system like this. At my current company in fact, it's formalized. We work X hours a week, and if you work any more, it goes to vacation. Actually,

I prefer a system like this. At my current company in fact, it's formalized. We work X hours a week, and if you work any more, it goes to vacation. Actually, you work X - 4 hours a week, every week the entire year with no vacation, such that it you actually work X hours every week, you end up with (52 x 4 =) 208 hours of vacation a year. So, for example, I'm in crunch mode for the next week working X+3 or X+4 hours a day. And then I'm taking a 2.5 week trip to Nepal a month or so afterwards. Crunch time happens, and we can't afford to thumb our nose at it, but this system means that it can never become the norm.