I've been using Keepassx and it's derivatives with the cloud services and now with Syncthing. I've been doing this since 2006. I think at first I was doing this with a flashdrive, then ssh, then Dropbox and now Syncthing.

Syncthing has really matured and is a great tool with my phone, tablets, Bitcoin full node and various laptops. I upgraded my Bitcoin Core machine hardware so it is able to do the file serving when I need a constant source.