I have almost quit my "real" job twice and go stictly consulting. My criteria to go pure consulting is funds to cover 3 months worth of expenses saved in separate bank account (a safety net) and atleast 3 months of work ahead.

Both times I said, if all continues as is, I will quit at the beginning of next month. The first time I had some major expenses come in and wipe out my savings and safety net money and the second time, both contracts dried up.

But such is life and the thing I always remind myself of is, "Consulting is Riding high or the horse running of you. Be ready and expect both."