I bought my first new XC vest in 2000, the standard Tipperary eventer. I finally upgraded and bought a new Tipperary (the approved style) vest for shows in 2020.
I still wear the old one A LOT; it usually lives in my truck. It is my gallop vest, my breaking babies vest, my “Oops, I forgot my show vest in the other trailer” vest. The old vest is just slightly lighter weight than the new one, it has one or two very small worn patches on the fabric at the arm holes, but otherwise is in good shape. It’s dirty, stained, and I would prefer it to get covered in baby horse spit than my nice show vest. I’ve had minor falls in it, and I don’t feel like an approved vest would have been any more protective in those instances.
Nice show vest is reserved for XC schools and competitions. It is just slightly more bulky and hot than my old vest; not a problem in a 30min xc school, but more noticeable galloping 10 horses on a muggy FL morning. Could the foam be deteriorating a little bit? Sure, I guess. But it still offers roughly the same level of protection it always has…it won’t protect me from any kind of crush injury, but it will disperse some energy and may soften a blow from a hoof or cushion a fall on uneven ground.