Most of the time I don't really want to have my yubikey on me all the time (in particular, I no longer have need of regular keys in my day to day life so my key

Most of the time I don't really want to have my yubikey on me all the time (in particular, I no longer have need of regular keys in my day to day life so my keychain isn't as important as it once was). I'm happy enough to put a cert on a key, maybe with an expiry time, every now and then or on first use. And it means I have to care less about what agent I'm running most of the time.