I haven't had a real vacation since 2003.
In 2007, the corporation paid me out for 15 weeks of vacation time. In 2010, they paid out 11 weeks. I earn 5 weeks per year, plus 2 weeks personal time and up to 4 weeks sick.
I take long weekends, and individual days to burn off time. With the end of the year closing in fast, I still have over 200 hours on the books. To reduce that, I'm taking two days a week off for the balance of the year.
Why don't I take vacation? Simple... I'm lead Engineer on several weapons programs. If I'm not there, chaos rules. All the patents are mine, and no one but me has designed even a single system component since 1997.
As a result, if I get hit by a bus, the company is in very big trouble. Thus, I have raised hell the Aerospace Division VP, who went to the CEO, who called me and promised me two experienced Engineers to mentor. One (recruited from Northrop Grumman) started this past May. He's learning the technology, but has a long, long way to go. The 2nd Engineer starts December 1. Maybe, next summer, I'll get to take of a week uninterrupted by panic stricken VPs and customers who won't talk to anyone but me...