I have hundreds of old 500 GB drives I use as backup.. take a few to work and leave them there as off site. Change them out for fresh when I think about it, usually ever couple of months. While it sounds like you have a good backup plan, that 'annually' thing bothers me, lol.
Annually is just one of the 4 back up systems. Each are staged in time so that there is redundancy in every time interval. By not over using the 1T SS Drive, there is a reduced risk of failure of it.
