[lojack]

I work for a company that doesn't advertise unlimited vacation, and instead phrases it as "we don't have a formal vacation policy, it's all up to your supervisors discretion."

Basically, as long as you're being reasonable, and you communicate your intention early enough for deadlines and staffing to be adjusted accordingly, they're cool with it.

The entire company culture supports a healthy work/life balance and leadership constantly drills it into everyone's head that what's important are results and not work. They also lead by example... my supervisor just took a three week vacation, where he was almost completely out of contact. His projects all slowed down and he had a lot of stuff to catch up on when he got back, but it definitely wasn't frowned upon. If anything, it was encouraged.