How long should I expect the factory battery to last on my '97 F-150 4.6L?

 

I've seen several posts here that describe them as very durable. I had one that was still perfect at over 4 years and I've seen longer posted here.

 

Which model? The BXT-65-650 is one of the best batteries ever (Motorcrafts are pretty damned good in general). I had one in my 93 Ranger for 11 years, traded the vehicle in with it two months ago, and we had two weeks in the single digits this winter, and a few days below zero, including 14 below, and the truck started every day. My mom had the same battery in her 94 Grand Marquis and just replaced it last fall (and that was because she left the headlamps on and drained it, she thought she should replace it).