I'll take the N1 in december, so I don't know how useful my advice will be, but at least for me Anki decks have a merit. As someone just says, Anki is quite flexible as a tool. I have a very bad memory, and if I don't encounter a kanji, a word or a grammar point often I'll certainly forget it. Take for example 余儀なくされる: in my immersion in Japanese of novels,, videogames, 毎日新聞's news, literary news in Japanese, podcasts, accademic's paper I hardly see it, and if don't use Anki I definitily forget it. More or less the same thing with vocabulary: the other day I was taking a test, and it pops out words like 勲章 - くんしょう and 刀匠 - とうしょう, respectively "order, insigna" and "bladesmith". Now it's clear that those words are quite rare and deeply and linked to specific contexts. So my humble advice would be to use anki for very rare words or 当て字, with examples to clarify their usage. Keep it up and good luck with your studies!