I have 3 Kryptonites. I keep all three keys on a Gerber multiknife, a Leatherman and a keyring. Keyring stays at home. Gerber or Learherman always are on my for rides, the Gerber in-town and Leatherman with my good bikes. I have to lose both knives and I'd still have my spares and be able to order more.

(Gerber is small, light and smooth. The Leatherman is a real tool (best pliers I have ever owned for a lot of jobs) but bigger, heavier and tends to catch jersey pocket stitching and rip them. So it lives in a leather pouch. That works super except it is slower to lock and unlock; something I don't do on long rides (no lock) but all the time in-town.

Yes, I am always riding with several keys I don't need. A lot better than getting there and realizing I have the wrong key because I decided on a different bike at the last minute. (Two of the locks live on my in-town bikes full time. Third lives on a small backpack.)

This has worked very well for this space case. I've had to order keys a couple of times but that isn't a big deal. Amazingly I have not lost that Leatherman yet. (Knock on wood.) My sis gave it to me 35 years ago. The Leatherman folk love seeing it when they support rides or I am at a trade show. Some of them have never seen one so old. It's like an old Stanley 9-1/2 block plane. Simply a really good tool.

Oh, goes in my left jersey pocket or right pants pocket. It has come out of my jersey pocket once and a car ran over the Leatherman. (Two keys bent and replaced, small rip in the pouch which got a permanent Barged leather patch. Leatherman came out completely unscathed. Once in 35 years I can live with.)