[whichdan]

It depends on the company. Technically it does mean you can "reasonably" take off as much time as you want. Realistically, it depends on how much vacation everyone else takes. If you see that most people are taking off 10 days, you'll probably get 10-15 days. The main benefit for your employer is that if you had something like 20 days off and only took 15, they don't have to roll over the extra 5 days or explicitly pay you for them.

I would try to get in touch with a couple current employees and ask them roughly how much time they take off each year - there's really no other way to know.