Keeping a seed phrase safe for 18 years
Most crypto losses are not hacks: they are lost papers, forgotten hiding places and nobody knowing where to look. A baby's wallet has to survive 18 years of exactly that.
Two copies, two places
One copy can burn, flood or go out with the recycling. Keep two, far enough apart that one event cannot reach both: a fireproof safe at home and a bank deposit box, or your safe and a grandparent's. Neither copy should say “bitcoin”, “crypto” or “seed” on the outside; an envelope marked “For Ann at 18” is enough.
Steel outlasts paper
Paper and ink are fine for months, uneven for decades. Stamping or engraving the 24 words in stainless steel survives fire and water. Plates made for this exist, and so does a cheaper route: a steel washer set and a letter punch. The first four letters of each word are enough, because every BIP39 word is unique by its first four.
A look once a year
Pick a date — the birthday works — and check that both copies are where you think, legible and complete. Look at them; do not type them anywhere to “test” them. The watch-only balance shows the gifts are still there without the words leaving the paper.
A letter for the family
If something happens to the parents, someone has to know that the wallet exists, where the copies are and what to do with them. Put a short note with your will or family papers: what the wallet is, where the two copies are kept, and that the words open it in any BIP39 wallet at the paths printed on the card. The note should say where the words are, not what they are.
Will the words still work in 2044?
BIP39 phrases have been the standard since 2013, and every major wallet reads them. The card also prints each address's derivation path — Bitcoin m/84'/0'/0'/0/0, Ethereum m/44'/60'/0'/0/0, Solana m/44'/501'/0'/0' — so a future wallet can be pointed at exactly the right accounts. Keep a copy of the card's addresses with the words, so whoever restores it can see they landed on the right ones.
Handing it over at 18
- The young adult installs a wallet of their own and writes down its new words.
- Together, you restore the baby wallet from the old words and send everything to the new wallet.
- The old words are now worthless; destroy both copies.
Moving to new words matters: the old ones have been in other people's keeping for 18 years.
For a larger sum
One phrase on paper is a single point of failure. For more than you would carry in cash, consider a hardware wallet that holds the key on a device, or a multi-signature wallet where two of three keys, kept by different people, are needed to spend. Both take more care to set up; both survive one lost copy.