I will keep the magnets if I ever get into this in the future, but not the platters. I’ll just safely destroy them and dispose of them.
So far I only had 3 laptops and no desktops. I had 0 HDD failures, since I only ever had 3 of them so far.
The oldest one is more than 17 years old 80GB 2.5" Fujitsu HDD.