My Outback went just over 8 years. I killed it jump starting the Wife's minivan, which had a battery that shorted internally. Sigh, best oem battery I've ever had...
Replaced with an Autozone, which was replaced exactly 1 year later with another Autozone, replaced exactly 1 year later with a NAPA battery. That's been in there for 5 years now. Weird with the Autozone batteries, but they were good about warranting them. That was supposed to be their 'best' battery. I didn't want to be stuck, and was sick of the short life, so I got the NAPA.