Pole barns seem to be economical & simpler to build, but what are the negatives to them? How long can you expect the poles to last? It seems like once the poles rot, the building is trash. I had a deck w/ treat 4x4s in the ground for 10 years & the person who bought the trailer pulled the poles out to reuse. They were like new. However, I think they would have to rot eventually. I see a lot of debate about using cement or not. Does anyone have any really old pole barns. How long can you reasonably expect them to last?