I think it's a typical transfer from working for someone else to working for yourself. I charged the same as I was making at my last job and earned a whopping $2400 my first 6 months. I gradually raised my rates, but still had no clue about overhead and billed hours. I stuck with it, but it's the reason most people don't make it more than a year or two.
As for the people that hire someone like this...I'll be here next year to cover the warranty...will they?
Dave
