My origional battery lasted about 3 years....when it started to go it would never leave me stranded, but started doing quirky things. Like the clock would be set to 12 and the cd player would cycle through all the cd's and it would barely turn over. If it ever sat over a day I would have to put it on a charger, but wouldn't hold, just give it enough to start.
So, I went to Costco and bought a Optima Yellow Top(best price I could find by far). Anyways, I have had the yellow top in for about 2.5 years now and a couple weeks ago it started doing the same deal as the factory one. So I don't think I am going to be able to get it to atleast 3 years....I will wait and see, not sure what the Costco warranty is on batteries.
On another note, I have zero confidence in Die Hard batteries....I used to only use those in all my vehicles. Then they changed manufacturers and they are $HIT!!!! My suburban ate them like candy, so I put an AC Delco in it and all was good. Maybe Sears has resourced now, but I will never give them a second chance, got stuck in the hood with the family coming home from the airport at 2am is never a good thing!

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