Took a 38 month old dead battery into Walmart last night. Since it had a 3-year free replacement/ 5-year total warranty and was only 2 months over the three years I figured I'd get near full credit towards a new one. NOT TRUE! I only got 37% toward a the new battery. Here's the shocking truth about how that works. A 5-year battery loses 1/60 of it's replacement value each month. So at 36 months it's actually down to 24/60 or 40% of it's value but since the 3-year free replacement still applies, it's credited at 100%. That all goes away on the 37th month leaving 23/60 or 38%. Moral: get your battery replaced IN the 100% period or suffer what appears an unfair decreased credit.