Having coins in your own wallet not keeping them in exchange forever is as important as making backups of all private keys.
Lately, i wrote that my HDD fucked up and i will need to replace it - https://steemit.com/bitcoin/@kingscrown/while-moving-backup-of-old-hdd-found-loads-of-oldschool-wallets
If you host many wallets ie to do Proof of Stake its also worth to just clone drive with all of the blockchains (that may take weeks or months to sync). Sure you wont lose coins if you have priv keys but syncing 3465346 wallets may not be fun. Do the clones from time to time and here is how to do it.
There are many ways to do it but i will tell you how i go for this for internal drives, you can tweak this in any way you need.
Get HDD, in my case Seagate Barracuda and USD to SATA/IDE cables
Download freeware from https://www.partitionwizard.com/free-partition-manager.html
Now this is easy. Connect the HDD to Computer, choose drive, click copy and paste it into clear drive. It will do a 1:1 clone.
Now the computer will restart in dos mode and do its job. I suggest leaving this overnight since it takes time to copy 1TB of data.
Done
Now if your HDD dies, you just put the clone, and computer uses it the same way it was. No need to install anything, change permissions - its the same HDD for the computer. I suggest this clone-backups done from time to time ie every few months.