Note: I haven't done the record keeping or recording of this technique yet, but I was wondering if anyone is using OF with The Pomodoro Technique? The work session "x's" can be done in the notes of a project or action, and then add them up and enter the time in the "Estimated time" field. The 'recording' part might not work quite as well in OF as in the Pomodoro method, but it could still be useful.
http://www.pomodorotechnique.com/
Bob