The blogosphere is full of questions about this. Some define it as saving passwords on the assumption that your demise will be too sudden or painful to allow an opportunity to pass them on. Others say it is everything you have ever typed, txt’d or spoken on a phone.
Passwords could be written down and secured in a safe place. Maybe you have too many passwords? Maybe you change them frequently (I’m not sure it matters much as long as they are strong. If quantum computing moves into the domain of hackers, your password will never be strong enough, or changed often enough to thwart them.
I have a small number of strong, but easy to remember passwords I use for billing accounts and critical email. I also have weak, easy to remember passwords I use for “fluff” accounts. (You know the free ones that only want your eyeballs (and proof that you have eyeballs so they can justify their CPM rates to advertisers.)
There is a growing list of password management tools. OpenID, Roboform, and KeePass to name a few. The concept is simple, a very strong generated-password using facts that only you would know for verification and recovery. If you bank or trade stocks online, you have probably encountered these without realizing it. Maybe your spouse or trustees should know what model your first car was, or the name of your favorite pet, teacher, etc.
I anticipate that this annoying password game will be obsoleted someday. Microsoft/Apple/Google/etc. will use AI, personal knowledge (that they can get from Facebook) and your DNA stored in the RFID in your system.
A more serious question to consider is “what” you leave behind – digital legacy or digital detritus? Or your private memories, stories and personal messages to those you care about. Randy Pausch’s, oft-quoted remark said it best. … I could put myself in a bottle that would one day wash up on the beach for my children…