My Td4, delivered on january 9th 2001 never missed a beat in the morning until the morning of August 24th 2005, not a tick came out of it, replaced the battery and up till now it's all ok. Remember one of my previous cars, a Peugeot 309 XRD was a couple of months old when one afternoon I started, without any problems, the car after work and drove to a gasstation a couple of hundred meters away, filled up the tank and when I wanted to start again no sign of life in the battery anymore, was completely dead, replaced by a new one and for the rest of the years I kept that car no more problems, so a battery can loose all power overnight and can also, without any warning or any previous problem, brake down completely in a second.