I use Keepass, I store the databases on Dropbox, I memorize the passphrases, and I store their private keys on a thumbdrive. I do worry about someone analyzing

I use Keepass, I store the databases on Dropbox, I memorize the passphrases, and I store their private keys on a thumbdrive. I do worry about someone analyzing each and every change to the database for some kind of information leak, but I also change the compound key every 6 months which should help.