What upsets MM is seeing my tire on the back of my bike jest keep a coming on back, and he is counting his in whole tires now.
..... and yet between the two of us we have NEVER worn out a darksider yet -- something incidental destroys them before wear out happens.
My best one got killed by a rust lump on the rim growing through the tube (yep, sounds kinda really slow acting, don't it? It had most of a decade to work its magic.)
This one might outlive me.