This is known in the education space, and tests like the JLPT N5-N1 are based on this! Also when learning English, the learning material and exams are based on

This is known in the education space, and tests like the JLPT N5-N1 are based on this! Also when learning English, the learning material and exams are based on this. The order of frequency is not strictly followed though, if you have to learn "Monday" now and "Tuesday" in a couple of days, it makes sense to bundle them all by concepts at once and learn "getsukasuimokukindonichi". So in Japanese learning, on a day-to-day it might seem like you learn random difficult-easy words or characters, but overall you only have to _memorize_ the top N characters/words for the next test and you'd be alright. I made a free website to memorize Kanji that works offline: https://core.cards/ https://core.cards/. Initially I did maintain a list of the top 100, top 500, and top 1000 (approx) if I recall correctly, extracted from Wikipedia lists, to learn Japanese Kanji. But now I've switched it to just follow the JLPT because they were almost the same.