Thumbs up to everything Leebo said, plus three caveats:
If you are a human being with metabolic needs for things like food, bathroom and rest, there’s a high chance that the item SRS schedule won’t perfectly align, since the first two levels span 12 hours and most people won’t stay awake until 4 am to apprentice 3 an item they unlocked the previous afternoon. When you take this into account, the fastest realistic timeframe for completing any given level is around 7 days 4 hours, since you need to account for about 8 hours of potential breathing room in case levels don’t aling with your sleep or work schedules
These level up times assume that you do two things:
a) do all reviews every day and twice on the day you unlock new level items
b) learn every lesson as soon as it pops up.
BUT that however is also a little sketchy, since a new level typically unlocks about 35 kanji, 3-15 radicals and about 60 vocab items on the fly, so what it means is that to keep those fast level up times, you’d actually have to put in 3 study sessions a day once every 8 days– once to initially “learn” the items, then again for the level 1 review, then once again for the level 2 review 8 hours later. As you can imagine, This is a grueling study schedule, which because of the not perfectly aligned 7 days means even if you start off level 1 on a Sunday, will have you eventually needing to do a triple study day on a Monday.
This is why even the most steadfast folks tend to take 8-9 days, and to vary slightly– it’s not that the speed is impossible, it’s that SRS alignment isn’t on a pure 24 hour or 7 day cycle so people have to work around that.
Even the level up times I mentioned assume that you have a constant level of motivation and time to devote to WK which is statistically speaking, rare and unlikely, not just for all user but for any given veteran user across their WK subscription.
Speaking personally, I managed to maintain that sort of schedule (time for me were 8-11 days on average, with the median being 9 d, 9h about) for about 18-20 levels, but after that point, because it was 7 months later, my work and school schedule had changed and also I started seriously studying for the N4, at which point WK took a backseat to studying grammar so that I could fill in the grammar gaps I had for the test, since I already know all the N4 kanji. The end result is that my last four levels have each taken like 20 days, and my current level is just hitting the 17 day mark. Now that’s not permanent for me, since after I take the N4 tomorrow I’ll re-align my studying time in other directions, with probably a renewed focus on WK in conjunction with a focus on reading fluency– while I won’t be pushing for 9 day levels anymore (my daily review count is already in the hundreds), given the time I’m budgeting it’ll probably be more like 15 days a piece.
All of which is to say, VegasVed, that if you’re trying to budget time, keep in mind that finishing WK is a medium (not short) term goal– from where you’re at you could theoretically finish WK in 1 year, but I would venture to guess realistically that you won’t get it done in less than 2 years, and that the average is probably somehwere around 2.5-3 years.