I replaced my batteries in 2010, on my 2003. I thought that was pretty good. Since we now live in Arizona, I do not expect next set to last that long. Batteries, tires and windshields to not do well in this state. I was lucky that when the batteries died that the truck was in my driveway. I think that it is important to do a "Load Check" annually in order to see how well the batteries are doing. I bought my new batteries at Costco (Interstate batteries). I was not able to get the same CCA as the OEM batteries, but due to the fact that I don't go anywhere that is below 40 degrees I did see this as a problem, and it has not effected the starting at all.