Ask HN: How Long Does it usually take to become profitable?

Supposing that I start up today, how long do you think would it take to become profitable. I mean to exclude here start ups that might go viral, or, on the other hand, start ups that might take much longer than usual. I mean to include on average, only, and without funding. Would you say one or two years?

If so, how would you support yourself during this time?