Comment by dbdr

    The novice said: "I will save my working files, but not my system and application files, as they can be always be reinstalled from their distribution disks."
    The master made no reply.
    The next day, the novice's disk crashed. Three days later, the novice was still reinstalling software.

If that's your situation, it might be worth backing up applications. However, there are better solutions that make this irrelevant. For instance, using NixOS, you can literally back up a single text file describing your system setup, and you can recreate the system from it automatically in minutes, guaranteed to be bit for bit identical.