IPhone battery dies quickly?

I have an iPhone 4S and this week it's been draining more than ever. I haven't been using it anymore than I usually do. When I get home from schools it's at like 10 percent which it's usually just at 60. Even when I put my phone alway and use it like 3 times the whole day it still does so quickly. 15 minutes after I charge it it's at 70 percent. I try closing out my apps fully and turning my brightness on all the way low and if still hasn't helped. What's wrong with my phone and what should I do?

Tips:
-turn on autobrigthness/reduce brightness
-turn off bluetooth/3G/4G/wi-fi off when not needed
-turn off location services and data push
-fetch email less often and autolock faster
-turn off equilizer
http://ipod.about.com/od/iphone3g/tp/iphone-battery-life.htm

I don't think its the brightness or the apps, i have had mine for 4 months and just had this start 2 days ago, i work for a major cell provider and have been told that when apple comes out with new phones they bug the old ones to get you to upgrade, i thought it was just a farce but now i'm starting to think it is true.

  • Why my iphone 5 battery dies so fast? I did a full cycle charge, disabled background refresh apps, turned off location services, turn off motion effect, turn of Bluetooth and 3G. A nnd dies fast, I think inn gonna get. A 5s. Because the battery is. Better
  • My new iPhone 4s Battery dies quickly? I got my white iPhone 4s a few days ago and I feel like the battery runs out pretty quickly… I turn the brightness down and completely shut down all off the applications at the bottom, but I feel like it still doesn't last very long… It'll go from 100 to 65 within a few hours… My sister has the black one and she says hers doesn't die too quickly. Any suggestions?
  • My iphone battery dies at 50 percent? How can I fix my iphone I got it in December but I didn't buy it directly from apple I got it from koodo where my phone plan is
  • My iPhone 4s dies at 18%-25% battery I have updated my iPhone 4s to iOS 6 about the week it came out… And now (a month later) it dies about 18% to 25% battery! What do i do! My phone was jail broken about a year ago but I took it off. I also just thought the update would take the jailbreak TOTALLY away. What do i do?