I used to teach full-time, at first traveling around, and later making everybody come to my house. I made a decent living, and didn’t have to have too many students; maybe 3 or 4 a day. But it came to be a pain in the ass. I got sick of unreliable students, and students who were just not fun to work with … there were a few good ones, of course, but most of the lessons were just tedious. Eventually I longed to not do it anymore, and I also longed for things like employer-paid health insurance, vacation days, etc.
Taxes were a complete pain, too. And the tax laws are not kind to the self-employed; you have to pay into Social Security as well. I kept just a little over half what I earned.
If you do take this up, I recommend you collect a month’s payment from each student in advance. If they don’t show up, too bad/so sad, but you still get paid.
I had a teacher who was rich enough to be extremely selective of students. If he didn’t like you, he fired you right away. That would be ideal; I still think about taking on just a few students of my choice sometimes. Teaching has its rewards.
But hey, if you’re willing to put up with a certain amount of crap, you can definitely make a living at it. It’s a rare enough skill that (in cities at least) you can charge a nice hourly rate. And some people really love working for themselves only. You should try it and see.