This is my experience as well. I had my final exams, 2 days with 5 exams each day at mid April (of more than a decade and a half ago, boy I'm getting older fast

This is my experience as well. I had my final exams, 2 days with 5 exams each day at mid April (of more than a decade and a half ago, boy I'm getting older fast). Most people in my class (around 40) had been studying since November, around 12+ hours a day. I begun studying in February, just due to my natural tendency to be lazy, I should have started in November too. But the point is that I tried all kind of timetables and ways to study in the next 2 and a half months. Early , late, all day, nothing. I discovered that for me what it worked was 4 hours at the morning, with a mandatory break every hour. Then lunch and maybe a nap or gym. Then another 3 hours at the afternoon. Every time I did less I was loosing time. If I did try to push it too much, studying till late, it was time lost sitting but not really advancing. Each hour of studying or writing had a effective time "on the zone" of around 20 min only. But what´s more interesting is that if I studied more than 7 hours, the next day was almost lost due to my lack of concentration. I managed to get the 3rd best results of my class, only failing one exam which I had only studied for 2 days. Only two students passed all the exams, and they were sitting very close and they confirmed me that they had been checking results between them when possible (yes cheating). So I guess that smart studying was more important that time spent seated. Of course there are other fundamental factors, but I actively tried to improve my study routine during that months, and I felt the difference.