The macOS/win32 SLIP-39 App

Open a terminal and run:

$ python3 -m pip install slip39[gui]
$ python3 -m slip39.gui

If everyone you talk to is recommending that you just write down your 12- or 24-word phrase and store it somewhere, why not do this?

It is estimated that 20% of Bitcoin is already lost in the first 10 years of its existence, stored in wallet addresses that can never be accessed because the corresponding "Private Key" has been lost, or the passphrase forgotten.

The statistical chances of anyone successfully passing a cryptocurrency wallet Private Key + passphrase or Seed to their heirs over a 50-year period is therefore very low. Since memory fades and "safe" storage places are lost, destroyed or forgotten, this risk actually increases exponentially over time.

I estimate the probability of successfully inheriting such a Paper Wallet + passphrase or BIP-39 Mnemonic protected Seed is probably less than 50%. Perhaps much less.

Have you ever forgotten a password to an online account?

Well, with a BIP-38 Encrypted Wallet + passphrase, there is no password reset option; there is no way to recover the passphrase.

If the Wallet is lost, there is of course no way to recover it, even if you have the passphrase.

This option is perhaps even less desirable than using a BIP-39 Mnemonic Seed phrase, because each and every Encrypted Wallet is exposed to this risk of loss.

If you already have a BIP-39 Mnemonic, and would like back it up using SLIP-39 for more security and recovery reliability, you can use the SLIP-39 App's Backup Controls to do so. After you create your Seed Data (or enter an existing BIP-39 Seed Phrase), select "Using BIP-39". This will generate a set of SLIP-39 Mnemonic Cards that backs up your existing BIP-39 Seed Phrase.

Later, when you need to recover your BIP-39 Mnemonic (say, to initialize a fresh replacement Ledger hardware wallet), use the SLIP-39 App, select the Recover Controls, and enter sufficient SLIP-39 card Mnemonics – and click "Using BIP-39" to reveal your original BIP-39 Seed Phrase. Then, proceed with Ledger wallet recovery as normal, using the BIP-39 Mnemonic.

This may not seem like an impressive feat. But, it is unexpectedly important and powerful! Your existing BIP-39 Seed Phrase is extremely risky; it can easily be lost or stolen. By using SLIP-39 to Backup your BIP-39 Seed Phrase, you can distribute the safe and reliable SLIP-39 Mnemonic cards to friends and family, and reduce the risks of theft or loss of your critical cryptocurrency accounts Seed data.

Learn how to use the SLIP-39 App to "back up" your BIP-39 Mnemonic Phrase:

Money that doesn't work has low utility and hence low value. There are often situations where you want to transport money physically, perhaps to buy something somewhere where you have no access to a computer, or by mail. Paper Wallets allow this.

Losing this Paper Wallet usually results in the loss of the funds held in it. But, not if you generate it from your Seed!

Just pick a derivation path you aren't going to use for your own personal wallets (eg. ending in ..99'/0/0), and generate some Paper Wallets (use each derivation path only once, of course). Fold them up so that the Private Key is not visible, laminate them and deposit funds into the wallet public address using the visible QR code.

The recipient can cut and unfold the Paper Wallet, exposing the private key and password hint, and can transfer the funds into their own wallet.

If the Paper Wallet is ever lost, you can recover the Private Key (it was derived from your Seed!), and transfer the cryptocurrency back into one of your own wallets.