GeoffisPure: Though the TiVo is a great device when working (especially while networked), let's not forget the fact that a significant number arrived dead on arrival in recent times. Maybe they sold them all quickly as the old stock was starting to break down in storage.
From what I can gather, the main thing that fails is HDD. When you think its reading/writing 24/7 plus seeking when your watching something... back and forth... etc etc skipping adverts - that is really a big workout for the HDD.
I plan to make a ghost copy of the drive one day so 'when' the HDD does eventually fail I can get it going again with a new HDD.