I can’t find anything at all regarding discussion, study or opinions on the question but I can tell you that it depends on the person and most likely, they’re experience in working at leveling/setting plumb.
Having used levels(spirit, laser, etc.) for decades, I can set an object like a stud, header or a picture for my wife and often don’t need to move it after checking with a level but my wife will often notice that a group of items aren’t leveled the same on a wall but she won’t be sure which one is off. There will usually be a few adjustments to all of them before she’s happy.
I can’t speak to the minutia but when I use Lemmy it just feels like a less popular Reddit to me. For me, that’s not a bad thing, just the vibe I get.