This particular one was put up for me by some local Mennonites who do that for a living. It's designed to last 4-5 years as far as the plastic goes, and the roof on this one lasted just that, thanks to a bad windstorm we had last October. I had the roof replaced back in January. The plastic is about 6 mil in thickness, and is made for greenhouses, and high tunnels. The biggest problems with these tunnels is salt buildup in the soil, and diseases. On the average, they need to be moved after 4 years, or else the roof removed for the winter months, and hope it rains enough to wash the salt away. The use of drip line irrigation, which only puts a small amount of water in the soil, is what causes the salt to buildup. I've gone to an overhead irrigation system, hoping to put more water down that in turn will leach the salt out.
Some growers will steam the soil after a few years, to kill diseases, but that is when they are mostly growing continuous crops, such as tomatoes. I try to switch my crops around as much as I can, but do grow more green beans than I should.
Yes, they are designed to be kept up for years, although they can be taken down and moved to a new location. I may have to do that if I want to keep using it long term.
