I have some 1TB SATA drives that are used for light online data (non-boot) but they are getting old. I though that by repurposing them to be archive drives, they might last longer.
Any ideas, or studies done on how workload affects lifetime?
For rotating hard disks (not SSDs), Google did studies on this a long time ago (2007).
Nothing makes a drive "last longer" -- all mechanical things eventually wear out (and even solid state stuff has a finite lifetime: SSDs have a maximum number of write cycles before they fail). What you should really be concerned with in terms of reusing drives are two major questions.
Note that even taking the drives offline (powered down in a closet) doesn't guarantee longevity - you may find that they won't spin up in a couple of years (a risk that increases if the drives aren't kept in a climate-controlled environment).