At Rocket Matter, I give starting employees 15 days of paid vacation each year, and I insist that they use them. They get no martyrdom points if they choose not to take their days. I’d rather work with a refreshed, rejuvenated person than someone who’s running on fumes.
Granted, other bosses are not like me, but as much as they want you to be churning out work, they do want you productive and agreeable. And if you put something on the calendar far enough in advance, you can manage the expectations of clients, bosses, judges, and whomever you will be dealing with.