I bought my Proform 8.5 Personal Fitness Trainer Treadmill in Dec 2008 and by May of 09..my belt was slipping.  I tried to fix myself with the horrible directions in the User Manual and tightened the bolt to wear a metal brace broke!  So being under warranty I ordered the part and the same problem still!  So after a few months I decided to call Proform...who I had a very difficult time reaching an actual CSR to help me.  They then set up a repairman to come out.  I've just had my machine fixed today and the repairman told me that I'd need frequent servicing because I used my machine for "running"...