I started working at 13, moved out from my dad's at 16, to the neighbouring country at 19. Now I'm 23.
Although I am very independent, I've not been very successful at it. I've always been poor, sometimes homeless, I've been living in a caravan for longer than I have lived in a real house, jobs and educations have been really hard.
But I've always survived, and am very grateful for everything that I have.
I really prefer to live by myself. I get miserable when living with other people, because they interfere too much with my schedule.
Right now things are looking pretty good. I am lucky enough to only have to work every other weekend to get by (because of very low standards and almost no expenses). And the rest of the time I'm painting. I started selling my art and getting illustration jobs, and it seems like I will soon be able to afford to live in an apartment. I'm very much looking forward to running water and a real kitchen.
I think that if you leave home with a steady income and a place to stay from the start (possibly some help from relatives too?), it's very manageable to keep it that way. I have a friend who faced very similar struggles to mine, but since her parents always could help her out with buying apartments and paying the bills, she has done amazingly well, got into her dream job and are paying her own bills by now.
What happens to me easily is that I become isolated. When I get a place to stay, I don't want to leave. It's like my comfort zone shrinks drastically the very moment I set foot in a home. I'm trying to remember to stay in touch with my friends. I don't need much contact, but complete isolation is boring.
If you're not moving too far away from your family, they'll probably remind you to come visit.
It can also be hard to stay structured and stick to routines when there's no one else to remind you of it. I just make a daily schedule and it works fine. But if I didn't have it, I would never wash my clothes or clean up.
And yeah, what the others said about the bills. That's really the important part.