Ask HN: living on savings while working on startup?

I'm contemplating quitting my full-time job to dedicate myself completely to a project that I've been working on part-time for half a year. We have no seed money yet and no prospective customers, but I feel that having me on board 24/7 rather than 3-4 hours a day + weekends would speed up our progress immensely and help us have something working to show to potential investors and customers much sooner.

Who here has dropped out and made no income whatsoever for some time while working on their project? Have you regretted it? Anything one should know before going through with it?

Thanks!