Not something we normally think about but too many keys on your keyring can damage the ignition barrel. 1 to 4 or 5 keys is ok. But, by the time you add a keychain, more keys, a pocket knife, a flashlight and so on, you may well find that, one day, the key won’t turn and the lock cylinder will need to be replaced. If you’re lucky, you’ll get a warning whereby the ignition becomes a bit temperamental and you’ll have a chance to sort it out before it fails altogether