Most batteries these days are going to last between 4-6 years, even high quality batteries. The best way to check the condition of your battery is to have it load tested for free at most local auto stores. They can verify the cells are in good shape. They will also check battery volatge which should always read 12.6 volts or higher when the car is off. It's very possible your battery may have a good year or two left in it, but the load test will give you a good idea. The test will also verify your charging system is putting out the proper voltage to charge the battery. I highly recommend this test, and have them do it a couple times.
As far as batteries, Optima batteries are good batteries for a daily driving car. If you don't use your car often, it sits for extended periods of time, and you take very short trips, then an AGM battery is probably not a good idea. AGM batteries do not like to sit, they like to be discharged and charged often. I have dealt with Optima batteries for the last 5 years. My first Optima (D34/78) died within the first year because my car only gets used on the weekends. I have talked with Optima and researched to find out the battery develops sulfication, or a condition where the electrolyte hardens on the plates and the battery can't hold a charge. Since my new Optima, I've had no problems because I use a trickle charger if I do not run the car more than a week at a time. The Interstate and Die Hard Platinum are good reliable batteries IMO, so you would be fine with either of those. If you don't run added accessories then you really don't need and AGM battery. My original Interstate lasted almost 6 years and may have lasted longer had I not killed it one day. Alright, sorry for the lengthy post, I just wanted to let you know of my experience with AGM's/Optimas. Any of those batteries are fine and I have not heard of any real issues with any of them.
'02 IS300 MSM LSD
Last edited by jasonm4; 09-29-2011 at 06:11 AM.