The researcher from the brain, Hermann Ebbinghaus made experiments how fast we forget something.
By his research do we forget after 30min already 50% of the content!
That is the bad news!
The good news is that after a month we still remember over 10% from the content.
If you would repeat the content it would look different.
So keep that in mind if you have to learn for an exam.
As always
stay happy
your 
