I think I've had mine about 8 years now and still going strong.
I've had the battery in my '03 Expedition for 8 years too. Starting to get a bit concerned about it, cause I don't know how new it was when I bought the vehicle from a dealer. It's still working great tho, but these modern batteries, they are either working great, or just die completely the next time you try to start the engine.
Can't tell what brand it is without pulling all those covers and cables off first.