Puppy doesn't need it, of course. A copy of your save-folder and a copy of the ISO, and.....you're laughing. 5 minutes later, you're back up & running again.
But I DO urge any Puppy users to copy their 'save' to a safe location. You can always replace system files; that's the simple part. It's replacing all those personal settings/tweaks/customizations that takes the time.....and it goes without saying; always save stuff to an external partition or - preferably - a completely separate drive.
It saves much future aggravation if you make sure there's nothing critical anywhere on your rig itself. If it does go "tits-up", there's nothing to worry about.....
Those who take hacking as a profession ... must be pissed off by Puppy. That's why they hacked the Puppy forums to vent their frustration.
I keep OS(es) and data separately, so any OS I use, I will be up in a few minutes.