I tried putting some stuff (mirror, fresnel lens) in my wallet, but I found it got too bulky. I now just keep some tinder, writing paper, Fisher pen refill, and plastic bag there.
I currently have two keyrings. One has keys, Photon Freedom, whistle and parachord lanyard. That's what I consider the minimum of kit for an urban setting. It's what would have been useful during the Twin Towers event, for example.
The other keyring has a load of stuff which I am meaning to write up properly some time, and I have a few items loose (small SAK, lighter).
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Quality is addictive.