I do illustration full time, it’s really time consuming, and doesn’t pay much (or on time). Every now and then I’ve tried working something else on the side but part time jobs always get in the way of illustration deadines etc.
When I started out though I was working four days a week nine to five as a technical officer at an art school, and I would do illustration work at night and on weekends, I don’t know if I’d have the energy to do that again! I did that for about two or three years. Now I’m broke all the time.