Ever since experiencing the 5 to 6 weeks of vacation that is standard the day you start a job in Europe, I take a minimum of 4 weeks a year. I started my own company quite a few years ago, so it's usually me paying for it now, but it wasn't always that way. Even with me paying for it, 4 weeks feels like the minimum required for me for a good work / life balance and mental health.
We have 3 months of unpaid leave each year, and I tend to use up about 2 - 2.5 months.
I don't have an unlimited policy, and honestly it's for the best as I would likely abuse it.
I'm in North America. I get 3 weeks. I take 3 weeks.
Edit for clarification: 3 weeks of paid. Unlimited if conditions require it (mental leave, sick leave, etc). I generally use 10 of my 15 days to extend 3-day weekends (if we get the Friday off for a bank holiday, I take the Monday as well). I save the other 5 for half days to do whatever.