I am on my third mill. My first was a nonadjustable schmidling mill which I sold because I wanted an adjustable mill. I used it for 8 years with no problem. My next mill was a monster mill MM-2 which I purchased in early 2008. I brewed 30 gallon batches, split with 3 other guys. I wore the rollers out on that mill in about 5 years but did mill ~800 pounds of grain per year. In 2014, I replaced it with the MM-2Pro with heat-treated 2" rollers. This mill is a beast and I think it will likely outlast me as I am back to 10 gallon batches.