Buy yourself 2 Ledger Nano S's (or comparable devices)
Setup one of the devices.
Write down the 24 recovery seed 4 times. Yes, 4. Double, Triple check every word.
Download the apps that you need for your coins.
Send a trivial amount of one coin (a dollar or so) to your new device. Note the exact amount of coin. Litecoin is excellent for this test, as fees are cheap and it is lightning fast.
Disconnect first device.
Open second device.
Configure second device as recovered from the 24 word seed. (Note- It really sucks if you mess up entering word 13)
Log into account, and confirm that the same amount of coin is in the wallet.
Send trivial amount of coin (maybe half of what you originally sent) to another wallet, like Exodus.
Confirm it shows up, and also note new amount in Nano account.
Disconnect second device and wipe off the keys.
Reconnect first device, and check that balance is again the same.
If you have an offline device like a Brother P Touch label maker, you can print your secret seed.
You have now confirmed both devices work, that your 24 word secret seed works, and that you can send and receive coins. You are now ready to use the device like the secure vault it is. And you will also understand the recovery process if you lose your device for some reason.
It is time consuming, but totally worth it if you are going to be storing significant amounts of cryptos.