Our trailer has been sitting for 2 years. I was checking the psi and only down about 5 pounds. Both tires on the passenger side have cracks in the sidewall and these have had tire covers on the whole...
We had a blow out in our motorhome years ago. Like, a grenade went off explosion. Nevertheless, sitting on the side of the highway, with a blown tire and RV damage, makes whatever the new tires cost seem really cheap. It doesn't hurt my feelings at all to buy a tire when I even think I ought to. The thing is, I knew the tires on that motorhome were probably in need of replacement. Lesson learned but good.