I never studied as much as I was told I should be studying. When I was at University people were so obsessed with getting in the recommended number of hours (around 40 a week I think?) and pulling all-nighters in the library before exams, but honestly I didn't see the point? I mean, I understand wanting to do well, but there's no point spending all day studying when you're not really going to pay attention for half that time. You need to actually retain the information, which you won't do if you only stare at it without really taking it in and engaging with it. I kinda learned that the hard way early on, when I tried to spend the whole day studying as I was apparently supposed to and I just didn't get anything done. Different things work for different people, but it seemed like a lot of people are too focused on the time without really figuring out the best method of study that works for them.
I'm a morning person, so I studied solidly for about 5 hours (either 7-12 or 8-1) and then I stopped for the day and let myself relax and just forget about it for a while. I always got consistently high marks, so evidently it worked for me. xD