My most used "key ring" is one of those things that looks like the old curly phone cords. It's at least 15 years old and I keep it on my wrist most of the time I'm not in the car or it's not in my pocketbook. There's my house key, salon key and keys for both cars.
Then I have another key ring with the keys to my storage room (one for the locked gate, one for the room) that's just an old silver ring
Then an USAF key ring with my personal mailbox key and the key to the salon mail box.
Then I have ANOTHER one with the key to my mailbox in ATL with the key to get in the front door.
THEN ANOTHER key chain (and this one is actually a chain

) with duplicates of all the above keys that I keep at home all the time.
As you can tell, I hate having a heavy key ring but I have a lot of crap I have to unlock. Plus I have 3 different safe deposit keys (mine, Dad's and brother's) in a jewelry box ;)