Why did the Car Battery dies pre-maturely?

are you sure the batteries are dying? did you have them all checked? it could be your charging system. the voltage regulator could be bad or even the alternator. also, do you have an amp and subs and all that crap in your car? if so you would need to upgrade your battery so you dont stress it out too much. go to advance auto and have your starting and charging system checked. also if you have any of the old batteries, bring them along to have them tested.