If the battery life in your iPhone 4S is getting worse and worse, or it just won't hold a charge, you can easily perform a DIY replacement. This can help you get lots more life out of your device and prevent having to buy a new iPhone before you absolutely have to. If you're soon to be out of warranty or otherwise not covered for exchange or replacement, or if you're just a DIY type who wants to learn more about the inner workings of your iPhone, we've got you covered.