My current job has zero sick days, zero vacation, zero holidays, zero vacation. I just simply don't work when I don't work.
I will add that I work from home and I run a division of our company, so yes I do have a boss (the partners), but they give me free reign for the most part. You'd think that it'd be tempting to just take a ton of time off, but part of my salary is commission, so that kind of keeps me motivated. I'd say I've taken a total of 3-4 weeks total time off this year including a family death, birth of a child, and a ski trip. It's hard to quantify because I often work later at nights after the family has gone to bed.
Long story short, if you value your job, you'll be reasonable with your time off.