Sound advice, but I'd like to add a related issue from the other side. I'm lucky that everyone in my team is highly motivated, but that has its challenges as well. In this context, I have several people who I regularly have to encourage to not keep working overtime, to stop work at a reasonable time, to switch off phones and email and enjoy a bit of private life. They all know they can take all their allotted time off (and, in fact, enjoy a lot of flexibility on top of that), but they still push themselves hard.

This doesn't make my life easier, of course, but I'll happily live with it given their work ethic is like gold dust. My point, though, is that making sure someone gets time to recharge their batteries is not an employee's problem; it's a shared problem.