Purchased 3 TivoHDs in 2008 ~ one with Lifetime and the other two with monthly service. Now, five years later, my TivoHD with Lifetime service is constantly rebooting. Two TivoHDs with monthly ($9.95) service are fine. All 3 units have been left on 24/7, placed in friendly environmnets, & used about the same. Can not help being suspicous. Any comments?