I am looking for opinions on car batteries. A little back ground first, I have two vehicles, a 2003 Monte Carlo and a 2002 Durango. I bought the Monte Carlo used in 2003. The Durango was purchased in 2004. The Monte Carlo has a Duralast battery ( not an Ac Delco like I would have expected) that was already in it when i bought. Not sure why the Monte battery was replaced BEFORE it got the car. The Durango has a Mopar battery in it, I assume original. Neither vehicle has any sign of starting or charging problems. I am thinking of replacing the batteries in both vehicles before winter, just to be on the safe side and based on age. It seems that car batteries can just fail at any time, due to temp or vibration. Probably true for new and old batteries. From the internet, I found: << Most auto batteries are made by just three manufacturers, Delphi, Exide, and Johnson Controls Industries. Each makes batteries sold under several different brand names. Delphi makes ACDelco and some EverStart (Wal-Mart) models. Exide makes Champion, Exide, Napa, and some EverStart batteries. Johnson Controls makes Diehard (Sears), Duralast (AutoZone), Interstate, Kirkland (Costco), Motorcraft (Ford), and some EverStarts>> In the past, I have always purchased Ac Delco batteries. Delphi makes the batteries for the Delco brand. Johnson Controls makes the optima and duralast brand. So, opinions on which to get, Delco or Duralast? Either brand battery costs around $90.