How long should an iPhone battery last?

I have an iPhone 4s that I bought this past January. My battery lasts roughly 3 and a half days with the odd couple of minutes of phone calls. And to check my phone periodically. Now is this normal for an iPhone battery when left on or should it be lasting longer?

I think that is an example of good battery life. My 4S was lasting around 2 and a half days between charges and I have no voice plan (hearing impaired).

  • Why does the last percentage of my iphone battery takes so long to charge? I have noticed that the very first percentages (1-20) of the iphone battery charges very quickly, but when it comes to the last percentage (99-100) it takes like 15 minutes to charge!
  • Used Iphone 4S: How long should the battery last? If you're trying to gauge the batteries health, generally speaking, I'd like to know your opinions on two things: 1) How long SHOULD a full charge last if it the phone is ON, yet is not put to use at all. Meaning no calls made nor accepted and no anything else. No pictures, game playing, nothing. 2) How long SHOULD it last if used from time to time to make calls and browse the internet.
  • How long should the iPhone 4S battery last? I have my brightness in the middle most of the time and mine only lasts about 3-4 hours if I'm using it. Standby, it's life is about 4-5 hours
  • How long should my iPhone 6 battery last? I purchased an iphone 6 couple days ago and the battery life is not that great. I doesn't last me a day with what I so call normal usage for example: all i use is texting a few times a day, mostly using snapchat and browsing facebook. Can anyone tell me on their experience with Iphone 6 and how long does their phone last them? Cheers.