Sometimes the simplest technology is the most useful one. For me, it's a simple pomodoro application that I've created to show how much work I have been doing and to remind me to take a break from time to time. While it seems to be counter productive to take a 5 minutes of break once in a while, and a longer one after a certain hour, I have found it that I could work until the very last minute more refreshed than if I take long dives into work for hours on end.
An important detail that I noticed when I take long dives into work without breaks is that although I tend to get a lot done at those dives, when I come back to work on the very next day, I tend to be less motivated and have more resistant towards doing or continuing on the work. Compare to the days when I follow the pomodoro time where I can ease into work much more easier on the very next day.