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Use a hard drive...
Personally, I wouldn't rely on hard drives to store my private keys/seeds for long time (more than two or three years).
Some hard drives have a short lifespan (depending on the manufacturer).
I, once, stored all my important files on hard drive and didn't use it for two years. When I tried to restore them, I discovered that most of them were corrupted. So, I wouldn't advice anyone to use this method.
Definitely it's not practical but it can still be alternative just to make sure that you have back up options as long as possible. On the other hand, it's still best to write it down to a paper such as being provided by the ledger. Use a great pen that its link las for a long period of time and then it'll guarantee the safety of your private key or recovery phrase.