Well, let's see.. I admin my imageboard at random, sometimes I'll be on it for 12 hours straight, sometimes I only jump on for 5 minutes every few hours.
I work about 3 - 5 hours per day on this. Sometimes I'm reading guides and picking up info on here during that, but every day I do a check on analytics, PR, adsense, etc.
I'm currently running 2 MNS but I'm about to upgrade to running 7.
However, I'm also currently developing tools to make my work a little easier. This will actually also be going into my portfolio so I can pick up a job as a programmer, which will make my working hours jump up quite a bit.