This becomes very obvious to one's self if you learn an instrument or another mechanical/procedural thing. For example, cramming 4 hours into guitar is less use

This becomes very obvious to one's self if you learn an instrument or another mechanical/procedural thing. For example, cramming 4 hours into guitar is less useful than 1 hour over 4 days cause of sleep. Sometimes I will struggle with something for quite a bit towards the end of a practice session, and then I will get it right on the first try in my next session on the following day. Hell, there are so many times when I go to my guitar teacher and I tell him "yeah so i practiced this part of the assignment over the past week and I could never figure it out" and then I try to show him the issue and I play it mostly correctly to my surprise. With something like learning a language, problem solving skills, a code base, new maths, or wtv, it is less apparent because the mind can delude itself, and it is much harder to delude yourself with actual physical movements. You either do it, or you don't...