ODesk time tracker might not be right for me (emphasis on "might"). The issue with me is that I work in brilliant bursts. It's some kind of genetic problem probably. The result is usually miraculous and given the fact that there are only a handful of people on the planet who can figure out the little nuanced conceptual problems I'm solving and have solved, I like to log hours as an estimate. I realize that isn't fair, but it's also not fair that I'm not running certain people's businesses and instead providing super inexpensive labor for things that Percona or RedHat charges $400 per hour for. Other times, the client tells me that they have spent two weeks trying to solve something and just can't and that's why they need me. So I spend an hour and charge an hour, but probably wrote code for 20 minutes. I sometimes have stared at something for 30 minutes and done absolutely nothing, then walked outside and stared at the sky and then I realized what was wrong. Should I log that 20 minutes of sky gazing and 30 minutes of staring at a problem? Not sure. I think moderation and careful review of results should obviate the need to pour over screens. If you spent $40 to solve a procedure or piece of code that would take an entire team weeks to solve at a cost of thousands of dollars, consider the ODesk marketplace a huge savings.
Caleb, I think you would be better off charging a fixed rate for your jobs. This way the client is paying for results, and it doesn't matter whether you do the job in little bursts or you do it all at once. This does mean that payment isn't guaranteed, but if you either ask for an upfront payment and/or set small milestones so you aren't depending on a huge payment all at once, and you are careful about the clients you choose, it shouldn't be that much of a problem.
It happens, start the tracker after inadvertently selecting the wrong client, forget to stop the tracker when done and go on to some other task.... When monitoring freelancers on behalf of clients, I found one freelancer that apparently left the tracker on while surfing p*** sites. Yep, caught all the evidence. I assure you, that was not part of the agreed upon scope of work.