I've had a 4 year warranty on some Dell systems. I requested a warranty extension online and had to answer a few questions by phone, but was able to do it. There were multiple machines and it was for a large corporation so risk vs reward for them might have been good enough to extend them. I know they will work on systems not under warranty for a price, but for only system under 5 years old. Anything under that and they won't touch it. As for laptops I have never been able to get anything but a 2 year warranty on batteries. They just accept the fact they will wear down after use.