Time in school is finite. If you have five euro in your pocket you know that you can only buy a certain amount with it. The money in your pocket will run out just like your time in school. There are 167 days in a school year and if you divide that by your number of subjects your time decreases significantly.
When you look at your calendar you can see how much time you have remaining, and the best students use that time wisely. They will organize because they realize that you’re in school for six hours a day close to 1,000 class hours in a class year. They are not passengers in class, they’re not passive students. They use techniques to get prepare their brains to learn efficiently in class. They use techniques to revise the work they’ve learnt in class because they realize they can get a six-hour advantage every day over their competitors simply by being more productive during class time.