There’s no ‘wearing it down’ - age is age.
If anything, unpowered drives die faster because lubricants slowly harden over time. Ah least a running drive is unlikely to suffer that fate.
Also, any drive can lose magnetic cohesion on areas of the platter - with a running drive that’s maintained by a system like ZFS, these areas of magnetic loss can be automatically discovered and corrected.
Everything I’ve read (and from my own anecdotal experience) drives on a shelf die every bit as frequently as running drives, if not more often.
But in the end, don’t go doing anything just because you feel like “you have to”. I have a dozen smaller drives (500GB to 1 TB) that are just waiting for a purpose. I have a plan for them, but it’s not urgent. Eventually they’ll go in a Proxmox/TrueNAS/UnRAID box, when I can find a motherboard for the right price with low power draw (the drives will be the worst power consumer anyway).