At day 1, before the lecture starts, you know nothing about that topic i.e. 0%. At the end of the lecture, you learned 100% of the fresh information, however well you know it. On day 2, if you don't revise the subject you lose 50-80% of the knowledge of what you learned within 24 hrs. This happens because all day long you see, hear and experience a lot stuff, which is not always important. So your brain will just get rid of the unnecessary information to make space for new important ones. And when you don't think about the material you learned again, your brain thinks that it's not important as well, and hence it clears up that information as well. This process of forgetting learned information continues and by the day 30 you only remember 2-3% of what you originally learned! And now when you again go back and see the topic, you'll have to study it from the point 0% -- complete waste of time and energy! So what is the lesson learned here? All yo...