Some climates are wet or tropical, and rust happens quicker. Here in Costa Rica I decided to buy corrugated aluminum sheets and bury them 8" in the ground. The interior floors are concrete. Hardware cloth is above ground and behind the aluminum sheets. There are also wood louvers that can be latched at night and open in the day for ventilation. In almost 9 years, not one problem. Since we're older, it's comforting to know that no real maintenance is needed.