It’s actually 6 years and hardly a myth . Seen several blowouts on perfect looking tires Ozone will kill them with zero miles . and these are rough if you look . Why risk on a 70k car ? I guess you’re referring to the metal valve stems ?
I've got twenty cars...hmm that's 80 tires and 95% are 10+ yrs old (some 20+)....never had a blowout. Obviously not driving on any that have rot or cracking. My problem is having tires that are round. Also flatspotting from sitting.....and keeping air in em all....about 5 have slow leaks about 2psi a week....
https://www.raceramps.com/car-storage/ramps/p/flatstoppers/ could try these , but 20 cars worth might not be cost effective .
https://www.facebook.com/groups/BuickGSOwners/permalink/10159814039472336/?mibextid=W9rl1R Being flipped for $85,000 thousand dollars on fb and already “pending “. I need to know How to make $20,000 in a couple months .