Iphone 4 Battery

[mayennaise]

My phone's battery is running down at an alarmingly fast rate! I'm presuming it is because it is so old!! The phone is a hand me down as I'd never be able to afford an apple product!! I've ordered a replacement battery and it comes with the tools required to put it in but I'd like to know if it is a job that I could do or should I leave it to someone who knows what they are doing??
Also - will my phone keep all the apps and info that I currently have on it when the battery comes out??

[ivor4781]

http://www.pcadvisor.co.uk/how-to/apple/how-replace-iphone-battery-3346693/

[mayennaise]

Brilliant - thanks ivor4781