Ruby Freelancers had a great discussion [on time tracking][art]. As a freelance developer tracking and billing time is how you make money. If you don’t bill enough time you don’t pay bills.
I’m always wondering if I could bill more time so hearing them talk about how much time they bill each week on average.
I shoot for 4 – 6 hours a day, of billable time, 4 days a week. Some days aren’t quite that good. Typically a bad day means I was estimating all day, not billable work but stuff that needed to get done. It’s work but not billing clients.