I'm at the point with my side project where there aren't enough hours in the day to do everything that needs doing. I work 9 hours a day, then come home and have a long list of product development and hamfisted marketing tasks, which I can never get done.

Early on, when it was all just code, my spare time was enough. Now, I would seriously quit the day job if I could (still at $0 Revenue after 6 weeks of being up and running - trying to get the word out, but it's harder to get noticed on the internet than it used to be), but I have a family (who needs health insurance). So, I'll keep sacrificing sleep.