I think several bags on my Prevost were at least 20 years old when I sold the coach.
Could be original 44 as well.
I replaced 2 that in the rear were exposed to road debris what grind outer rubber showing fabric under. Even at that shape the bags would still hold 120 psi I tested them at.
Inspect the rubber. If you see lot of crack - replace them. If all smooth, just carry a spare. Any truck shop can replace them on the road.
Than some preemptive freaks replace parts at 25 percent of their life.
To each of his own.