[Linda Buquet]

Sorry TNT but my answer has to be (as usual) it depends.

Depends on your niche, conversion rates, commission rates, how many sites,
how much traffic, style of marketing, how good you are, how smart you work.
I could go on and on.

But one of the main factors (after niche and $$) is marketing style.
If you are not good at SEO and can't afford to do PPC and are forced to do constant link exchanges, articles, social marketing, just to keep traffic coming in - then you will always need work lots of hours to keep traffic & sales up.

If you can afford some tools that automate some of the work and
can afford PPC to keep traffic flowing OR are good at getting top
search rankings AND/OR have lots of user-generated content
always creating new spider food, then you can probably spend less time at work.

I know lots of affiliates that have LOTS of sites to maintain that work
70 hours a week just like brick & mortal business owners. I also
know some affiliates that make good money only working 4 hours a day.
Most of the latter I think are either black hatters, PPCers or
highly technical and have lots of the work automated.