I quit my job around 9 months ago. Finding too much of time on hand I subsequently started work on a new app, got my friend to join me and we got into Start-up Chile. It's been a great journey but I'm so glad that I did not quit the moment we were profitable. It has taught me the most important thing you need to learn while starting up, being efficient.
I always suggest everyone who has a product to not quit until it is virtually impossible to keep up with a day job. You then become a time management champ and know how to do more with less :)