I wind up carry many keys myself. House key, mailbox key, two keys to my car, key to my wife's car, and a key to where I work. That's six keys. The key to my mom's place is kept somewhere else, as is the key to my sister's place at the shore.

I keep spares to nearly all the keys in my wallet. I've heard too many tales of people "just running out the door" and getting into trouble by forgetting their keys. I always have my wallets on me, so I always have keys, should I forget my keyring.