Last trip out before I got Covid I blew 5 trailer tires, yes 5! 24' enclosed with 205-75-15, two were only two months old, one was brand new spare, the others just used spares. I had a 64 T-Bird convertible with a ton of extra parts, so it was right at the brink of overloaded, obviously was overloaded with those tires, would still have been marginal with 225-75-15 tires. I do keep used tires for spares but try and buy new ones everytime one blows out. When it is 10:00 on a Sunday in the middle of nowhere you do what you can to get where you need to be. There is no such thing as "rejuvenating" tires...