@sil There's definitely something weird and interesting going on here. You routinely damage the rings but not the keys themselves? Are you sure you're not just buying really bad rings?
I've been using the same ring for as long as I can remember (maybe as long as I've been using keys?) and it's as good as new.
@mavit see, everybody says that. I don't know why it happens. I promise it's not that I'm just buying shoddy rings :)