[Klathmon]

Personally, I encrypt my backup/recovery/setup keys in a CSV file using a password that I have memorized, and send them to family members to store in their accounts/cloud storage.

But safety deposit boxes are a good choice too, just be careful to balance your own convenience. If you can't easily update your backups, you're really unlikely to include new accounts in them

[tacocataco]

What happens if you suffer a TBI and can't remember the password?

I guess you'd have bigger problems at that point.

[tshaddox]

Perhaps an estate lawyer could be trusted with the information in case you become incapacitated or dead.

[fennecbutt]

Doesn't that just mean that Apple's X character key is protected only by a password presumably of lesser length?

I suppose a phrase works too, and easy to remember.

[thfuran]

That also means you can't easily update passwords.

[microtonal]

You could put your passwords in 1Password or iCloud Keychain, so you only need to back up those credentials.