I lost a bunch of newsletters I'd written about 20 years ago (
) because of a HDD failure - and I have absolutely no excuse because I worked in IT...on an IT Help Desk (which somehow makes things worse).
Although I had hard copies of the newsletters, I missed one. I've been over compensating ever since. I have two "cloud" backups, Time Machine, NAS drives (one of which has spudded out - just as well it's mirrored! I must replace the faulty one...), and the ubiquitous portable HDDs (which are stored in a 1940s safe that looks like a refugee from a Sam Spade movie - in case of fire).
I have everything I've done backed up since "The Great HD Disaster of 1999".
Everything. Multiple times.
As for saving things in a format that can be read, I can remember something from the dim, dark past that PDF was touted as the archiver's choice. But, 1. You have to get "it" into PDF and 2. Is it really a suitable archiving format? It has been around for a long time but...shrug.