When you're working for yourself or in a situation where you can work more hours and make more money (freelance, sales, whatever) then you can lose money by being cheap. Anything that can be hired out at a lower hourly rate than your own should be hired out. The catch is that you actually have to spend that time you saved working and earning income!

If you have a fixed salary, though, you might as well do those things for yourself if you have the skill.