In your position, I would consider getting past my resistance to fixed time frames. Yes, people can pile on extra requirements but there are ways to manage thi

In your position, I would consider getting past my resistance to fixed time frames. Yes, people can pile on extra requirements but there are ways to manage this -- first by strong communication, and then just mentally figuring in some buffer time (1.5x up to 4x like some people have said) in drawing your original estimate. Also, you can start iterating in smaller-scale projects and iterate gradually up from there. You can also ask for intermediate payments once certain milestones are completed. Thing is, fixed-budget projects have a lot of psychological advantages for people making these kinds of decisions, in addition to just providing very pragmatic ass coverage on their part. And in the end, if the money (and stress / time) tradeoffs work out for you, that should be all that matters. Also, once you're above the $50 an hour range it's better to bill daily or weekly anyway. There was a nice long thread about this issue a couple of weeks ago, I believe.