I replaced tires on our hauler 6 months ago, kept the best old tire and had it mounted as the spare. New stems on all of them and balanced.
Once upon a time,
I had another hauler backed into the driveway close to the house. I heard a loud hissing noise coming from outside so I went to investigate it. Both stems on one side had rotted and let go, causing the hauler to lean onto the house I had seconds to move it and tow it a few miles on deflating tires to the tire store. Strange for sure.