I had a very nice job (career if you like) and played in several bands at the same time. Not a lot of gigs and the money was not important (if you split by 6 people, the pay isn't all that good...)
Then I was asked to do solo-gigs using backing tracks. Rate of gigs went up and the pay was quadrupled. I had a 40+ -hour day job and three all-night gigs a week. Sure, I made a lot of money, but being married and a baby coming... My wife and I decided that we wanted to have more quality time. And so we bought just that: time for ourself. Unfortunately it was not possible to do my job part-time. Stepping down the career ladder was no option for the company. So we decided that I quit my job. That was the moment that I went "Pro". That was 6 years ago.

It all went pretty well. Sure, we didn't have the double income any longer. But I was making the same or more money than my regular job. Now with the crises and all the gigs got fewer. But I record bands and choirs with my mobile recording studio (48 separate tracks digital) and I do jobs as a sound engineer.
So you can say I still make my living with music. I am still self-employed. Though I love recording, producing and doing live sound engineering, I can happily say that the gigrate is going up again.

Mike
www.mikewever.nl