The nice thing about having a set number of vacation days is that there is an expectation that you'll use them. Having "unlimited" means you're expected to use

The nice thing about having a set number of vacation days is that there is an expectation that you'll use them. Having "unlimited" means you're expected to use them when you've gotten your work done and there is a lull. Except in many jobs, startups in particular, there is never a lull. So any time you take off you aren't "getting stuff done" and potentially look bad. The result, in my experience, is more frequent, shorter vacations like long weekends.