I recently got an iPhone 4s from a friend because he got a new phone. It was free, so I accepted it. Anyway, I noticed that the battery discharges after a few hours only. I wonder if there is a way to extend the battery life of 4s phones. Thanks a lot!
Make sure you have location and mobile data turned off when you are not using. My old iphone tends to eat battery as a beast when surfing the web. Also make sure you have turned off every background application after you are done with them. You could check out an app like battery doctor or something which will tell you what eats most of your battery.
The iPhone 4S is multiple years old. I guarantee that the battery itself is dying from old age. Most iPhone 4S users see 8 to 10 hours of usage. Buy a $20 replacement kit for the battery on eBay and do it yourself. There are guides out there, and it's not a dangerous fix. It's out of warranty anyways, so there are no worries there. After 1,000 discharges/charge cycles or so, lithium batteries in phones start to hold significantly less juice than before.