Key FOB : What do you do with yours!

[Boomer]

Bike jacket pocket, zipped up with my wallet.
Since I never ride without the jacket, not a problem.
If you are the kind of person who loses keys/wallets etc. then your biggest problem will be the cost of replacement fobs.
I urgently suggest that you figure out a routine so that you DON'T lose the fob. 

As for keys,... old tech, been there, fobs are a massive improvement! IMHO