You can optimise your study time by using the 45:15 rule. Read intently for 45 minutes, as this is your brain’s limit, and then take a break for 15 minutes. If studying for 45 minutes proves difficult, try using a timer when you begin reading and stop it when your focus slips. Do this a couple of times and you will sense how many minutes you are able to read at a time.
If you read hours on end, you will have trouble remembering what you just read. This is why it is so important to give your mind a break in between readings. Use the pause to get some coffee, use the bathroom or put a wash on. Also, you will make the most of your reading, if you study without procrastinations.