I've noticed that lately (I think with iOS 7.1 and above) my 5S has been using LTE data instead of WiFi when I'm at home or university (in dorms where there is wifi everywhere). Not all the time -- but I'd say about a little less than half the time. Turning off cellular data makes it stick to WiFi (with full 3 bars) which is fine but it's annoying to have to do that every time I go out and every time I get back... Say I'm watching a youtube video at home -- initially I'm on WiFi, then it randomly switches to LTE for a few seconds, then wifi for a few more, then LTE again. When I turn off cellular data, the wifi works consistently, so I know it's not something weird like the wifi signal being lost. I wouldn't worry about this before since my phone was grandfathered into the unlimited AT&T plan but now I'm on the 10gb shared plan so I am trying to conserve my usage... Is there any way to force the phone to use WiFi over cellular data without going into settings each time and having to turn it off? Should I take it to an apple store?