One can opt to save the keys on a personal computer wallet. The keys will be retrieved only by using a password.
Second, one can also prefer to print the keys on paper and keeping them in a bank locker.
If you stored on personal computer and get spoilt beyond repair. Which ways will you get your private keys back? Those personal computer storage of private key is not good to save keys. Save your keys to the place you have without the helps of electricity power supply to turn your system on before reaching your private key. Writing it out and save offline is the best way of saving private keys without much stress and is going to be good security again. Because if somebody touches it were you kept it you will know