There seems to be a parabolic decrease in mental fitness past a relative threshold of studying. Assuming topics are studied from most to least relevant, the mor

There seems to be a parabolic decrease in mental fitness past a relative threshold of studying. Assuming topics are studied from most to least relevant, the more time spent after the threshold will come at too great a cost to overall memory recall during a test. This is why I cram all the most important topics first, sleep, then cram the subjects least likely to appear on the test an hour before in the morning.