The clearest sign is having enough paying clients to cover your basic expenses without stress. Another sign is having work come in regularly from a few different clients, not just one. If you are already turning down work or struggling to keep up while still at a regular job, that is a strong signal you are close. Going full time before the income is stable is a risk that can be hard to recover from quickly. What do you think is the financial position someone should reach before making that move?