Drive failure in the 00s was really common. I lost 2 or 3 separate drives from different mfg over the course of a couple years. Newer drives are better but even in modern nas setups, I planned on losing at least 1 drive per year on a 4 drive nas even fresh out of the box.

Always keep data your care about in at least 3 places and in at least 2 different mediums with one preferably offsite. I like to have one drive in use, one backup that sync’s daily, and one that I keep in cold storage unplugged. Then swap the sync drve and cold storage drive every so often.