I've re-entered the business after years of treating it as a hobby. I eased back in by busking on the streets. There, if I made enough to pay for gas, meals, and guitar strings I figured the day or evening was a success. But to the point:

Now I have a steady gig for two nights a week at a bar. I only make $50 a night, with one night being a full night of maybe 3 or four 45 minute sets and the second being a "dinner show" where I pretty much do one long 90 or even 120 minute set. When the owner sheepishly offered me $50 a night I told him that back when money was a problem for me I'd have been damn glad to see $50 and now that money isn't a problem I'd consider it a paid rehearsal and worth the experience.

So now I'm getting 140 shows a year under my belt and being paid 7000$US/yr for going to "performer school", polishing my act and learning what it really takes to be a pro: consistency. Playing well when maybe you really don't feel like it. Making the best of a bad night or audience. Keeping your concentration when all around you are losing theirs.

If you're in this with the express purpose of making money, you're in the wrong business. If you feel a need to figure rehearsal time into your expenses, you're in the wrong business unless you're a session musician. If it takes you an hour each to set up and tear down your equipment, you might be in the wrong business and should definitely find and fix the problem.

Never play for free, and never let them pay you in food/alcohol, and you'll probably turn out OK in the long run