If it's important, or if you love your stuff, then always keep a backup.
I personally do three 5TB ext. drives, and only two drives may be at the same location at any given time. I'm also making sure only to use drives whose S.M.A.R.T. can be read without removing their enclosure.
Not sure who thought it'd be a good idea to make an external drive where S.M.A.R.T. cannot be read through whatever interface it uses.
I haven't found a definite favorite yet, but I've bought a few Western Digital external HDDs which have all supported S.M.A.R.T. over USB. I'm currently using their WDBU6Y0050BBK devices. They don't have the best reviews, but mine have worked just fine over the past year.
Contrary, I've had two Seagate external HDDs in the past, none of which supported S.M.A.R.T. over USB, and they died after about 10 years of sparse use (powered on for backup at least once a year).
I guess one could find what USB chip the WDs use and then compare with other drives, but no one writes such stuff in their product information. >:(