IPhone 5/5s data usage problem?

I'm still using iPhone 4, but my friend has problem with data usage with iphone 5.
How to solve this problem?

Um… Okay. Not quite sure what your question is exactly. If you have a problem with data usage--then I would suggest you stop using apps that consume data--Netflix, Spotify, Pandora, Facebook, etc.

  • Under settings on my iPhone, does the data usage include Wi-Fi usage? Because its stating a ridiculous amount and I've had my data off… And my Wi-Fi on. Does the total of data include the amount of Internet I'm using when on Wi-Fi? I'm so confused
  • Memory Usage Problem With iPhone? I have a tethered jailbroken iPhone 4(GSM 2012), i only have 3 apps from the app store downloaded, and a few more from cydia, yet my iphone says i've used up around 6.1gb out of the 8gb i have, i can't download any apps cause of this, yet i also don't know what's taking up the space, is it the cydia sources?
  • IPhone: settings cell usage vs AT&T's data usage number? AT&T has a number, by calling it will send you a text message telling you how much usage you have used on your data. But also in the iPhone there's a cellular usage count in the settings app which also tells how much data you have used. Both of my cellular usage counts are different. Which is right?
  • IPhone 5s AT&T Data Usage Problem? I bought my iPhone 5s about 2 months ago. Since I had it, my data has spiked up so much. I was on the 2 Gb of data plan for AT&T until I got my iPhone and they switched me to the family plan. When I had my 2GB plan, I almost never went over with my Galaxy S3. Now with the iPhone, I used 13.6 GB! My bill is now up to an extra $200! What do I do about this? PS: Last month I used 7 GB