If you have serious money in bitcoin

1. Buy a hardware wallet.
2. Load it up with your coins
3. Buy a second hardware wallet
4. Initialize the second hardware wallet with the 12 word wallet recovery phrase from the first
5. Put them in separate safe deposits with the 12 word lists.
6. Don't keep any additional copy of the 12 list and don't memorize it.
7. Use a mobile wallet with different private keys if you need small change.'

This way its harder for the robber to use a $12 wrench as a cryptanalyst tool.

*you really only need one wallet+list in one box and list in the other but if you have enough coin to worry about this then why not have 2 wallets