I bootstrapped a consulting business, and didn't have any savings at all to do it. I had to be profitable from day one.

I did not even have a laptop at the time (for network diagnostics and the like) -- I just had my experience.

I've had to learn an awful lot about resource management as a result of doing it this way, and I'm grateful for that.

presumably there was a significant cost in time and/or money required to gain that experience.

You've got to live anyway. Might as well pay attention while you're doing it.

I would argue that prostitution is profitable from day one..

That depends on whether your parents are perceived as VC's providing seed capital.

Now I really want to know what was in that deleted comment.

technically, I don't think that's quite true; a company can book profits even as it's paying off a loan which is bigger than the profits or even than total turnover as long as (operational cash flow) - (interest payments) > 0.

I think it's perfectly possible for, say, a company funded by VCs to be profitable from the start of operations, since the money that bought the equity isn't expected to be paid back.