The whole point of SRS is that you don’t get “extra” studying, that you rely on your memory instead.
I understand that I don’t have to use it if I don’t want to, but I feel like a lot of people will unknowingly mess up their studying in this way, so I’d like to at least say it out loud.
Srs is about optimizing your studying and creating long term memory as it goes, and both classes of items that can be studied dont fall on this. Recent errors means your study isnt optimized enough to work, and needs extra cramming, and new items means its too early for any kind of long term memory to be made.
My main criticism is that imo instead of recent items being all apprentices, they should only be apprentice I
It’s up to them how they use it. Wk cannot babysit everyone.
You can use the study tool right after a review or some time later. As long as you don’t use it right before you do the actual reviews you’ll do fine.
Personally I don’t use it. I don’t care how long I keep getting something wrong since eventually it will stick. I used to be concerned about leeches but I actually don’t care anymore 
Idk, I mean at the end of the day I run into most of the stuff I really want to retain in my daily Japanese reading practice. If I’m using the Japanese I’m learning it’s going to “mess with the SRS” in the way you mentioned either way. I think the bigger benefit of SRS is time management of what you study, not keeping yourself from seeing stuff in the meantime. If you used the review feature right before you did your actual reviews, I could see how this would mess with the system, however. It’s kind of like studying a bunch of dates right before a history test that you will never remember again after the test.
Thankfully the “extra-study mode” seems limited to items that will pretty much be in the apprentice level anyway and likely won’t mess with your long-term reviews.
Also, since the only two options are recently failed items and recently learned items, I don’t see how it could even theoretically mess anything up.
you’re learning a language … I just burned something this morning that I had seen watching something in Japanese yesterday and had mixed up the kanji with something else, looked it up yesterday realize what I mixed it up with and thought ok hopefully I can remember this…
along comes the kanji for burn…or course it’s burned…Did I break SRS by looking something up through immersion…absolutely not…nothing will be perfect and the kanji/vocab are you aren’t memorizing for pure recall …you are trying to learn a language…
don’t sweat the small stuff… you will forget things and have to look them up again … SRS or not 
How would anything that helps strengthen your memory not be conducive to learning? Looking over anything extra times can only help, not hurt.
Some psych research on spaced repetition suggest that there’s not much of a difference in benefit between expanding repetition and uniform retrieval. In other words, a flash card system where the intervals get dynamically longer (like Wanikani) might have pretty much the same benefit as a flash card system where the intervals are fixed.
Personally, I think this intuitively makes sense because if you think about how you learned written English, a lot of it was reading. And when you read English text you, for example, see the word “the” a lot, to the point where the intervals between seeing the word “the” in a single piece of text can be as low as a second or two. But do all these exposures of the word “the” somehow “mess up” your studying of the word? No, in fact, seeing it so many more times than most other words arguably reinforces it in your memory even more.
The main benefit of expanding repetition is that theoretically allows you to memorize more words in the same amount of time than uniform retrieval does. But both methods are effective ways to memorize words. It’s not the spacing that’s actually important, it’s the repetition. The spacing is just for time efficiency’s sake, there’s no negative effects to being exposed to a word ahead of schedule, as far as I understand it. If that was the case, then reading Japanese literature while doing Wanikani would be detrimental to your Wanikani performance. This is demonstrably not the case, as even Wanikani sends you emails to start reading Japanese around like level 20 or so, I think?
I’ve been in leech hell. This tool is a Godsend!
And it can only be used on very recent items or items you fail.
Once they are up in the higher levels SRS will see if you actually know the item, with no option to do extra reviews of the items anymore. Therefore this can’t be abused or hurt your recollection in any way.
Basically this, due to the way it’s implemented, it only helps people having trouble learning newwords and remediating leeches. I think that’s completely fine. If you ‘need’ the extra study for the later levels, chances of you burning them are rather low in the current system.
The lack of control over your study post-lesson but pre-guru is something i considered a weak point of wanikani. Glad it’s addressed in some way.
TL;DR The more you review, the better. But ain’t nobody got time for that. Therefore, SRS.
The point of SRS is to achieve long term memory with the least amount of reviews possible. Therefore SRS is a system that optimizes time efficiency, not memorization.
Think of it this way. If you review a word each hour of every day for a whole week that would make 168 repetitions. Compare that to the 5 repetitions that WK gives you, again for a week. Which of those is more likely to burn the word into your memory? Are you likely to suddenly start forgetting the word after the 5th day of mind-numbing repetition?
The larger number of repetitions is definitely better, but waaay more inefficient time-wise. You’re likely to do just fine with the 5 repetitions, so long as each one is done before you completely forget said word. That’s what WK tries to achieve. It tries to push the limit of how far you can go before needing to do a review. With each successive review that interval becomes longer, that is to say, with each review it takes longer and longer for you to forget that word.
But there is a problem with the fixed intervals that WK uses (4h, 8h, 24h, 48h, etc.), and it’s that some people have a stronger memory, while other people have a weaker memory. Maybe, for you, waiting 6h instead of 4h to do your first review would work just fine. You’d do just as well if you pushed your first review further out, and you’d save some time in the long run. But maybe I have a weaker memory and need to do my first review within 2h, or else I’d forget all I had learned, and would need to start over for the most part, which would be a big time waster. Each person requires specifically tailored intervals.
Having an “Extra Study” feature solves that problem for WK. Now it no longer has to fit a rigid time interval system onto everyone, but can instead let people decide if they need extra time with some batch of lessons. If you ace a given review session (you 100% it), it likely means you can go further without doing reviews and save on some time. Likewise, if you’re getting a subpar score, let’s say bellow 80% success rate, then you likely need to do reviews more often. How well you do also depends on how tired, stressed, hungry, distracted, etc. you are, for which no amount of calculations can account. If you feel like you need a refresher, then go for it. We’re here to learn a language - the more exposure you get, the better you’ll become.
@rangicus Why didn’t you just bring up your thoughts in the specific announcement thread where there is already discussions going on about improvements etc. and the WK team is discussing this?? Or do you, not want your critique read by them??
OP
as soon as you enter hell levels, this will be a blessing 
Go easy, this is literally their first post on the forums. They probably came here to make a thread asking about it without even knowing that thread existed.
@rangicus Since you have 13 people telling you in different words that you’re wrong, I’ll just add that this is at least a very common question from people with SRS so I get where you’re coming from. And I think you at least half had the right idea, in that there are ways (intentional or not) to “cheat” SRS, like reviewing something right before a burn review here, or even where things aren’t burnt, you’d put the item off far longer than it should be potentially, and just delay your own needed shorter term reviews. But yeah, this specific implementation looks good for avoiding that, so I don’t think you need to be concerned.
Ah, my eyes glanced over that one. My apologies to the OP. But my point still stands, as a more general suggestion then. Look around the forum for the question you’re thinking about as you might most often find answers to them. There have been many generations of WKians thus far to have pass these trials and so, if you look, there will be questions answered!
I don’t see how it could seriously mess up one’s reviewing. Even if it does, that will get smoothed by the SRS in time. Plus, everyone has a different way of studying. The fact it is completely optional is a great way to let people personalize how they study on site.
If we have any SRS experts here, they can (and probably should) correct me, but as far as I know, no, the whole point of SRS is that repetition is spaced in a specific way. It’s theoretically supposed to remind you exactly as you’re about to forget, which means you don’t forget when you otherwise would, while also not spending extra time on reviewing. In other words, you’re not supposed to ‘rely’ on your memory. That’s the point of using self-testing as a learning method, not an SRS. An SRS helps you to create and maintain a memory with the least reviews possible. That’s the point in theory. In other words, this:
Let me also say that SRS is not a magical formula that works for everyone, even if we assume the forgetting curve theory behind it is sound. The intervals may need to be tweaked. The number of reviews everyone needs may not be the same. Some people may find that reviewing learnt knowledge in different contexts helps way more than a typical SRS, and decide not to use one. I, for one, am able to lock certain words into my memory by studying them very intensely and creating very detailed and vivid mnemonics, and have done so a few times. The initial studying takes some time, sure, but for those, I only needed one learning session, and sometimes one review session. (I have a few examples on my mnemonics thread.) I learn almost everything else through repeated exposure during immersion (watching an anime, reading an article etc.), and I haven’t used flashcards to learn any language since 2013. (The last time I did it was for French, in Quizlet, in a word-translation matching game, and yes, it was in 2013.)
Ultimately, my point is this: as long as everyone successfully creates memories of new words and kanji, it doesn’t matter what method each of us uses. Some people will need more reviews to remember things, and I have to admit that the words I remember best are the ones I find so interesting that I recall them when I’m idle and fiddle with them in my head. Repetition works. If some of us need more of it, I don’t see why it shouldn’t be an option.
While I might not be an srs expert specifically, i am a cognitive psychologist. The most important thing for commiting things to long term memory is the repetition part, so the r in srs. More is generally better in this case. There is empirical evidence that spacing repetition is more efficient and robust, but it is no exact science. Studies have found very different intervals as being effective. The best interval probably depends on your specific ability and memory but also varies according to different factors (fatigue, stress level, interference with similar info etc.).
The next most important factor for long term retention would be combining new info with stuff you’ve already learned. This could be reinforcing kanji readings by learning more vocabs that use them or actually consuming content to put what you’ve learned in context.
So no, this won’t interfere. I think this misunderstanding comes from the more marketing oriented claim of having found the ideal method of memorizing just before your brain forgets. Just think about it, not every brain is the same, so how could specific, fixed intervals be ideal for everyone.
Anyway, thank you for giving me the opportunity to write this down, I’ve been wanting to say this forever
There should be an option to opt out of/temporarily deactivate extra study, so you don’t have it sitting there on your dashboard if you don’t want it.