IMO Interstate makes about the best battery out there. I've been selling them for over 15 years and I very seldom have one fail, I'd say less than 1%. If that battery is less than a year and half old any interstate dealer should replace it free if it's the 65 month. The 75 month has 2 year free replacement and the 85 month is replaced free for 2 1/2 years. Unless you buy an optima I don't think any other manufacturer comes close to that warranty.
As Rabbit stated make sure the alternator is working right. Make sure it's not overcharging because that will ruin a battery quicker than anything else. If the car sits for long periods of time without getting used you need to trickle charge it every once in a while or use a battery maintainer.