I always cringe at people who put a lot of keys and trinkets together resulting a heavy load on the ignition key while driving. In the past, I have seen cases where the key just came out of the tumbler but didn't shut off ignition. Imagine the load on an ignition key where vibration always exists and then add load that's 10x (maybe even more) the weight of the key itself.
I separate my other keys (house, garage) from car keys. The key for one car has only the remote fob for that car attached to it; no medallion, no pendant, no photo holder, no flash drive, no keycard, no ID card, no lanyard, no nothing else. House & garage keys are on a separate chain.
This is safer in a way that if you lost a key chain, it would be limited to the key for that one car or the key to the house or someone else's house. Granted that a key doesn't exactly have a house address printed on it, but it's still a remote possibility that it can be used inappropriately.