Re: what is the average battery life, in years of an I-phone 4S
Welcome to iMore! The iPhone 4s does not have a user replaceable battery, but can be serviced by Apple or an authorized service provider. Apple's litium ion batteries are designed to hold 80% of its original capacity for 500 complete cycles (draining all the way then charging all the way). Apple offers a battery service, which costs $79 plus shipping. You can find more information and schedule service here.