I've always done hourly because the clients were not able to specify upfront exactly what they wanted, and priorities would keep changing. Additionally they wou

I've always done hourly because the clients were not able to specify upfront exactly what they wanted, and priorities would keep changing. Additionally they would find that I'm good at other things and can help in ways they didn't anticipate. Everyone benefited. I would second hourly until both of you know the relationship. A fixed price contract has so many ways that it can go bad and a good contractor will be fighting you on any scope that you try to introduce. Unless you know for sure that you have ALL scope buttoned up I would go with hourly or daily rates. If not the relationship can become adversarial very quickly.