What belongs on a card.

Yes

Worth writing down.

The common thread: irreplaceable, rarely needed, catastrophic to lose.

1. I

   Recovery phrases and keys

   Seed phrases, hardware wallet backups, encryption keys. There is no support line for these.

2. II

   Master passwords

   The one password that opens your password manager, your disk, your archive.

3. III

   Codes to physical things

   The safe, the alarm, the storage unit, the building. Numbers people write on a wall otherwise.

4. IV

   Two-factor backup codes

   The single-use codes you saved once and have not looked at since.

5. V

   Where things are

   Not the documents themselves, but the note that says which bank, which folder, which drawer.

No

Leave it off.

1. I

   Everyday logins

   Hundreds of site passwords you use weekly belong in a password manager. Rewriting a card for a shop login is absurd.

2. II

   Anything you change often

   If it rotates monthly, the card will always be out of date. Store the master, not the churn.

3. III

   Files

   A vault holds names and secrets as text. Documents, photos and keys as files belong in encrypted storage.

4. IV

   Someone else's secrets

   Storing a colleague's or client's credentials makes you responsible for them. Usually not worth it.