Why does my iphone 5 battery drain so fast?

Hi, as so many other iphone 5 users my battery is so bad and doesn't even last me 2 hours! I'm currently using iOS 7 and have tried literally everything in the book, replaced the battery, turned off location services, turned off parallax and Bluetooth ect ect, literally everything that you could find online about this problem! However I haven't tried factory resetting it as I will lose all my music ect if I do, but if that's a sure shot to work than I'll have to sacrifice it! It's obvious that the problem isn't even with my battery as I had it changed and it's still terrible, is there maybe some other problem with my phone that I'm unaware of? My phone is over a year old and isn't covered by it's warranty anymore so I doubt apple can help, if anyone could offer any advice it would be appreciated!

The best way to find out what's wrong is create a genius bar at the Apple Store. They won't replace the battery for free but they can tell you whether if the battery is actually bad or its simply a software issue. They can run a diagnostic on the battery and get info about your battery.

Its because of global warming. The world is been affected and our phone is the prove of it. If I would be you I would start writing letters and training birds to send letter because from now to 3 day phones are not gonna work because of global warming. That dude is wrong! I'm right!

You have not mentioned that you kill all apps regularly?

That is vital with any i-device to control battery use or drain.

Double-hit the Home button and flick everything off the top of the screen, then (this time) reboot the phone.

Kill all apps as soon as you are finished with them, and reboot it about once a week.

Most apps have no effect if left in the background, but a few are badly written and continue to take CPU power, and others deliberately run for various reasons.

My iphone 5 is around 18 months old.

I leave everything permanently enabled (Wi-Fi, bluetooth etc.) and a Pebble smartwatch permanently linked by bluetooth - and the standby life is about two days. (It's a lot longer without the Pebble app runnning, I never normally kill that).

That's on it's original battery.

If killing the apps does not work, you have either a dodgy battery or a hardware fault in the phone.

2 hours seems way too quick but are you on it constantly? If your not then there's a fault with the phone but the good thing with Apple is that they will generally replace it for you.

Other things to try:

Lower brightness (DO NOT USE AUTO BRIGHTNESS)
Turn Wi-Fi off when your not in the house.
Turn Wi-Fi scanning off constantly.
Turn mobile internet (3G/4G) off when your in the house.
Always have Bluetooth off unless you need it,
Turn your GPS/Location settings to battery saving mode or something along the same lines. Don't use the high accuracy mode unless you really need it.

They should help. If not, it maybe a fault. Do you overcharge or undercharge your battery at all? Always charge from around 10% through to at least 90% and remove once done. Never leave your phone on charge overnight. Once a month, it is good to charge your phone from 0% through to 100%.

Also, have a listen to see if your phone charger makes a slight buzzing or humming sound. This could be a faulty charger and maybe the reason for your battery being poor. And are you definitely using an iPhone charger and not an iPad charger?