"Hope for the best, plan for the worst..."
Generally good advice if you are talking about sizable companies, data centers and the like, but in one's personal life (if you are a techie) this can get out of hand.
I have always had a network in my home going as far back as the early 80's, and I have always gone to great lengths backing up lots of data. Now, some 30 years later, I have multiple external drives and two very old machines that I use solely for backing things up. Problem is, I am still (to this day) backing up some stuff that must be close to 30 years old and though I constantly promise myself that someday I will review what I am backing up, I never seem to get the energy to go through that task - and instead, I just buy yet another big external drive and keep backing up.
Why do I still save program code from languages now dead? Why do I continue to hold onto Windows fonts that date back (I think) to Windows 3.11? I have close to 20,000 digital images and I still back them up, seemingly sure that one day I will go through them and actually throw away the pictures I inadvertently took of my own feet.
Sure, hope for the best, plan for the worst... But sometimes the worst is self-inflicted, and while I have spent decades ensuring that my "main machines" are clean and up to date, I now have more space occupied in backups than I do in actively used data.
And why didn't I get rid of stuff as the years passed? Well, though I am fairly sure that DOS-based Ryan/McFarland COBOL is not going to make any comeback in these days - if it does (!!!), I will be ready with the programs I wrote for it back when I didn't have grey hair and wasn't a member in good standing of AARP...
There's no such thing as dumb questions, only poorly thought-out answers...