I switched to “On” for the same reason: I want to get as much practice as I can so that I feel very confident if/when my SRS level increases to like Expert level that I really can answer the tricky ones, and not that I ‘just got by’ by making it past the easier ones.
For me, I think it’s partly because deep down I’m pretty much a perfectionist (even though I know that’s not really healthy for me, and I try to ‘let go’ of perfectionism all the time; it is just a persistent trait of mine). So, that means that I like to feel like “I’ve really got it” before I move on, even if that means I’m over-prepared and could have advanced earlier. But anyway, that’s just me.
As for the ghost review experience: Personally, I like that ghosts will stack up if I make too many mistakes in a certain period of time. What it signals to me is that I’m ‘going too fast’, and need to slow down (or even temporarily halt) doing new lessons. So, I will slow down, and focus on just doing reviews until my ghost count gets down to a more reasonable level. Say, below 20, or better yet below 10.
Currently I have over 60 ghosts, and it’s because I added too many vocabs to my overall reviews, and I’m working through them bit by bit; but that also means my grammar reviews are being slowed down as well, so I am starting to miss some of those and they are piling up as well. [I chose to always do *general* Review sessions, rather than splitting them by grammar/vocab, since I want to eventually get to a point where I have the right balance of vocab and grammar so that I am proceeding steadily with grammar, but also fitting in a balance of vocab along with it.]
So, I haven’t been doing any new grammar lessons for a while, and I’m even removing some of the more unfamiliar vocab items from my reviews, trying to pare down vocabs to get more in line with the number of grammar items I already have going on. It’s a slow process, doing a few reviews, removing a few unfamiliar vocabs from my stack, occasionally getting a grammar review wrong (thus generating a ghost), and not really working-down the number of ghosts because the number of vocab reviews is still quite high, diluting how many grammar reviews I do per session.
But I’m okay with it, because, like I said, this accumulation of ghosts just signals to me, “Yep, you still need to keep the brakes on, keep slowing down, until you start getting those ghosts to go down as well.” Eventually, I will get there, and then I’ll have a much better sense of how I should balance vocab with grammar.
I suppose I could take a short-cut and just remove, for example, all N4 vocab from my reviews all at once. But I’m okay with just doing it a bit at a time, as I come across unfamiliar vocab, and just removing them one by one during reviews.
I guess the thing that makes me all okay with this is that BunPro is very flexible, and if I really need to I can always just remove a large chunk of vocabs, and I could also reset all the ghost reviews as well. But like I said, I like having them around as a reminder that I need to slow down.