There have been a few that have done it near max speed and I think the record holder was like 4 hours behind, but expressed having had sleep issues for unrelated reasons in their level 60 recap post.
I’m all for going “fast”, but 60 in a year is not something I recommend. Easiest way for me to summarize it is by quoting the guide.
Select quotes from "My Journey of 368 days (+ The Ultimate Guide for WK)"
Chapter 6 is just me telling you not to go full speed (read it also).
Everyone wants to go fast. I get it. I’m the dude that named their thread “My Journey of 368 days” after all. I don’t have much of an opinion here to tell you to do otherwise, or do I? Please hear me out here: I’m a college student with too much free time. I had the time and motivation, so I did it.
My first argument for full speed not being necessarily a good thing is that the last 30 levels won’t be as productive to your Japanese learning as the first 30.
Don’t get me wrong, the last 30 levels are still very useful. Imagine not knowing around 1 kanji every 10: still annoying, don’t you think so? But this is an interesting concept: Maybe you can go faster for the first 30 levels and then slow down a little and focus on other areas of Japanese learning
Wanikani works so efficiently that some people end up getting to level 60 with barely studying any grammar. In my specific case, I definitely neglected my reading practice just to have a cool title on my level 60 celebration thread.
At the last 10 levels, I was doing 400 reviews every day while also trying to keep up with my other Japanese studies (and life!!!). Not everyone has the same time, mental energy or interest to go full speed. We don’t need to.
Slowing down to 7d or 8d levels instead of 6d 20h gives much more consistent and flexible scheduling and most people go slower. Unless someone is able to put in diligent student levels of effort every day to do WK + grammar studies + immersive material going at the fastest pace on WK is a bad idea.
It’s a different story for people already sitting in the middle levels, but those who are in the early levels and single digits should just stick to doing their best at more realistic year end goals. IIRC, the admins said the average clear time was like 1.5-2 years. Plan accordingly. Considering joining threads like WK study budy, monthly progress, leaderboards, or the skytree.