2 Separate Blowouts on RV Yesterday. Learned Important Lesson on Tires

so here is a thought, on my wifes car i got 2 sets of rims...winter and summer tires
about 4 month out of the year the winter tires are on the car, and the other 8 they are sitting under the lean too, or in the shed, depending on where i am when i switch em

do you think them sitting for that long would be bad for them too, or are we talking longer term then that?

Again, I am no tire expert, but don't think I would worry about that. When I worked at a dealership in the early 2,000's, we stored customers winter/summer tires when they swapped them out. I do remember we put them in "tire bags." Just big plastic bags. Garbage bags would work if you so chose. (Not sure why)