You might not have considered this before, but did you ever notice that you can actually impair your recall and memory by reading something too much?
I'm not referring to literature here. You can definitely gain deeper understanding and meaning from pieces of literature each time you reread them – not to mention enjoyment! But in general you are not trying to memorize text like that.
There are types of text however, where you need to understand, digest and then learn what you read. You obviously need to spend a certain amount of time absorbing and understanding the material – this kind of rereading too, is fine.
But the danger arises once you have read enough to understand what you need to understand. The next step in your learning is to assimilate it and commit it to memory and rereading is often a form of procrastination when it comes to memorizing.
It takes effort to learn what you need to learn once you have understood it. For many, the process of understanding new material can be enjoyable and satisfying, but the memory work can be tedious for them. But you need to take this step. (And this part too, can become satisfying in its own way.)
But here's the rub. If you just read and reread these texts, and I know that many students do this, in the hopes that it will stick, you will be sending your brain a stub message. You will be telling your mind not to bother remembering the information! Your mind will assume that it will see it again and that there is therefore no need to retain it. Sounds crazy, but it's true!
You need to make yourself recall the information as soon as you know you understand it. You need to test yourself regularly during and after reading and you should only reread with a view to fill in any gaps you find in your knowledge when you do try to recall.
This will be a different kind of reading. You will be scanning the text looking for the parts you found you could not remember, and concentrating on these. You may find you did not really understand them as well as you thought or that you just did not give them the attention they required the first time around.
In these cases, rereading is useful and necessary.
But reading passively from start to finish over and over, day after day will do more harm than good! Your mind will switch off and stop remembering. So be warned!