We would like to purchase a used Jeep Cherokee(we haven’t decided on a style) as a “work” vehicle ie. haul dog, camping, home improvement projects, etc. We live in central Texas and A/C is as important as the vehicle actually running. We don’t want to have to install a “new” system(CFC-free?) when it eventually goes out. How far back can we go (in which styles) that we won’t have to worry about that?