I'm personally using KeePassX, and so, all I need is the kdbx password safe file, the key file, and software that opens it. The password file has backups, and is synced to multiple locations; the key file too, and it's something I can re-download from the internet from multiple locations; and there are multiple implementations of the software for different platforms. So for myself, I don't worry about this angle.

As an alternative, I read that other people print their password list from time to time, and put it in their actual safe or a bank's deposit box.