When enabling a hot spare, I always do a drive block check. This takes little CPU or memory and it prevents the disaster of discovering a problem with a drive during a rebuild.
QNAP Specific Pro Tip:
Forget about hotspares md9 and md13 make these run ALL THE TIME so they age with the rest of the system. Have a coldspare in a drawer instead
Only 3 of my NAS’s are here. Others as far as 125 miles with users that I don’t trust to pull the right drive. Also, drive only spins doesn’t seek which is mostly what wears out. In your use case dolbyman, your advice is correct.