When we review seed backups, holders often ask which format is “best.” The honest answer depends on how you store it, not what it is made of. Over forty backup reviews since 2022, we have seen every format fail — and every format succeed.
Metal plates
Cryptosteel and similar products survive fire and flood better than paper. They fail when stored in humid basements (corrosion on letter tiles), when assembled incorrectly (reversed word order), or when the holder loses track of which plate corresponds to which wallet. We have found three instances where a client owned two metal plates with identical word sequences — a duplication error that provided false redundancy.
Paper cards
Handwritten BIP39 cards are fragile but legible decades later if kept dry. They fail in predictable ways: fading ink, water damage from apartment leaks, and disposal during moves. One client nearly shredded a card thinking it was an old shopping list because it was stored among receipts.
Encrypted digital copies
Some holders keep encrypted files on offline USB drives. These are not seed backups in the traditional sense, but they appear in our reviews. Failure modes include forgotten passwords, obsolete encryption software, and drives that stop reading after a decade in a drawer.
Co-location remains the dominant risk
Regardless of format, the most common problem is storing all copies in one building. A fire, flood, or burglary that reaches one copy usually reaches all of them. Geographic separation — genuinely different cities, not different rooms — is the single most effective improvement we recommend.
No format replaces policy
The best backup is the one your family can find and use under stress. That means a written map of what exists, where it lives, and who is authorised to access it. Format choice matters less than documentation discipline.