Let’s face it…this is the last thing any artist or dreamer wants to hear. “Don’t quit your day job!” Because it implies that they need a viable source of income because whatever they’re doing, be it painting, or writing, or acting…is obviously not going to cut it. But I’m going to tell you that I hope I never quit my “day job”…no matter how successful I may or may not be at my craft. I hope I always enjoy the simple things.
Why you should consider quitting your day job: There is something to be said for giving your art all that you’ve got. That’s your time and effort. It’s hard to make a book happen when you’ve got only an hour or two a day or a week to give it. And even 
those hours are the last, burned out hours of your day/week. That’s not going to make anything happen for you. You have to be willing to dedicate time and worthwhile effort to your craft. For some that may mean making the scary jump to doing it full time. If you spend anytime watching Shark Tank, you know those guys (and gals) think anyone who is serious about being an entrepreneur (and an author is a kind of entrepreneur) need to devote 24/7 to it.
Why you perhaps shouldn’t quit the day job: Not only does it keep you in touch with life (thus giving you ideas and inspiration about the world), many of us (hopefully) are doing something that we enjoy or 
enjoyed at some point. I know I am blessed to be doing so. Most of the time, my “day job” is being a stay-at-home-mom (yeah, one of those jobs I can’t really quit) and part of the time, I’m a zoological educator. I LOVE what I do. Teaching people about animals…interacting with exotic species…sharing messages that, even if only 10% of the people I talk to take me seriously, allow me to make a difference for wildlife and wildplaces.
In the end, the decision is up to you. What is your path? It all depends on your goals. On your life. On what makes up your day, your week. And it depends on your personality. I’m the kind that needs to go, go, go. Never a dull moment for a writer/stay-at-home-mom/zoo educator on the side/crazy lady. But it’s fun. And I’m doing it.