You must have been pretty good at billing every single hour you spend on your clients. I was once told that it's unwise to expect to bill more than 50% of the

You must have been pretty good at billing every single hour you spend on your clients. I was once told that it's unwise to expect to bill more than 50% of the time I spend, so I've been sticking close to $target_income / 1000 for the last few years. The actual ratio of billable to unbillable hours probably depends a lot on what kind of contracts you get and what type of work you do.