Q: how long does an alternator last? on 2005 Ford F-150

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
I was traveling on the freeway and heard a grinding sound and thought something was dragging. I stopped and everything underneath was okay, but then my car wouldn't start and no power to windows etc. I think it is the alternator, how long do they last?
(1) Answer
An hour to the life of the vehicle.

How's that for a range?

I'm not being funny either - I mean that you could have a faulty alternator out of the box, or you could never need one ever. If this is the original alternator in your 2005 truck, 6 years is not unreasonable. I would strongly recommend a high quality rebuilt unit (like from Ford) to replace the one you have.