O.K., this is honestly a new tire question...I think..

I would think that the materials in all tires are basically the same. So an RV tire that should be replaced at about 7-8 years due to deterioration, would have the same properties as the tires on the family sedan or minivan.
So, those tires probably should be looked at hard, and probably changed around the same anniversary.

I had to change out the tires on our minivan at about 40K miles, not from wear, but from dry-rot, as the van is parked out in the driveway...and it only had about 7 years on it.