If you are focused on ‘peak performance’ and/or ‘optimal productivity’, it is particularly important (in my opinion) to recognize as early as possible when it’s time to stop working.
There is a point, or a line, every evening at which you are no longer producing high quality work. In fact, you might even be sitting at your desk, thinking that you’re working, but accomplishing nothing (significant) at all.
At that moment, it’s time to disengage & unplug, because every ounce of energy that you spend after that line has been crossed would be far better invested into tomorrow’s tank.
The Healthy Path 