[mac01021]

If you get a stream of tiny tasks from your client, maybe hourly billing is the way to go.

I'd they present you with a project that you agree to deliver in 6 weeks and then mostly leave you alone in the interim, it's probably a different story.

[seanwilson]

In the 6 weeks scenario, when would you consider fixed price over weekly? With fixed price, there's a large incentive to be efficient and you can juggle more than one project at a time if you want to.