Rarely save. It doesn't sort by save time but by post time so the order is all fucked and I can't bother to go through it all. It's like 10-20 things from months ago and then a wall of posts and comments from 4 years ago lol
I save almost every post I upvote for some reason and some posts I disagree with and want to return to.
Kind of turns the save feature into a useless one and I recognize this, but for some reason I can't stop (and I NEVER actually return to any of the posts through that feature)
Can't quantify it but it's abysmally low; mostly because when I save things, it's for when my gut tells me there's a more-than-likely chance I'm gonna need to refer to it later. Theoryposting, effortposting, source link lists, et cetera.
Very rarely save, when I do it's mostly helpful posts or things I want to read later that I flag for re-visiting. To put a number on it maybe 2-4 things saved a month, but I upbear nearly every comment/post I interact with
I deleted the two comments I accidentally saved a few days ago. Much more efficient to trawl through several pages of posts to find what I wanted to see again.