That's the tricky part: I carry a USB drive which I make sure has the latest and most up to date file (for example, when I have to sign up on one-off online sto

That's the tricky part: I carry a USB drive which I make sure has the latest and most up to date file (for example, when I have to sign up on one-off online stores). Every so often I will manually back it up to laptop/desktop/cell phone/tablet. That's a minimum of five separate devices, and I'm not sure I'm ever carrying more than 3 of them at the same time. It's definitely not six-sigma, but I'll accept it for now I guess. Of course, all of this is in addition to service provided 2FA where applicable, e.g. Google, banks, web hosts, via SMS/Authenticator.