I haven't used a metal key ring for decades. I cut off a few inches from a leather shoelace, string my keys on it, match the ends and tie a single knot. I've found it a great deal more reliable than any key ring or chain. Lasts several years, then I cut a few more inches off the shoelace. I think the leather shoelaces I bought in 1973 are almost used up and I'm gonna have to buy a new pair, dang it.
Only downside is that taking a key off (for example for a mechanic) is a pain, because the knot gets pretty tight after a while. If I had to do that daily, I would not like my solution. In fact I probably do it half a dozen times a year, which I can manage.
Edward