Today I overslept for four hours! Jetlag is maybe the worst of the first world problems.
Recently I started tracking my time more accurately using the Harvest desktop app. I used to input how long I worked on a certain project by the hour but I once I built the habit of starting/stopped timers I think I prefer it.
If you work flexible hours, it makes you think about your time carefully, aware that you have a target of billable hours to hit. I've found myself more focused, knowing that I should stop the timer if I'm distracted by another task for too long.