A rested person can solve in minutes what exhaustion argued with all night.

The same problem meets two entirely different people depending on your state. Tired, you argue with it for hours and get nowhere. Rested, you see the shape of it quickly and the answer follows. Nothing about the problem changed, which is worth remembering the next time you are convinced that pushing on through the night is the responsible choice.

When a task starts fighting back late in the day, note where you got to and stop. Return to it early. The hours you save doing this are considerable and almost never counted.