Hi. I just bought an iPhone 5S and I've activated it with Ting. It's running iOS 9. It seems to be working great. I've never owned an iPhone before, although I have an iPod Touch running iOS 6.
I am using Google Voice with the iPhone. I have the Google Voice app installed and it's working fine, although so far I've only used it on wifi. I'm waiting until the iPhone case I ordered comes in the mail before I start using the iPhone out of my house.
Once I start using the phone out of the house and I'm not connected to a wifi area, such as on the bus, I only want to one app to use cellular data -- and that's Google Voice. I want to be able to read any voice mails and texts on the go. But I don't want any other apps to be running in the background. I guess I'm just worried that my data usage will become more than I want.
So, before leaving my house, I plan to shut off background refresh for the apps that have the option for shutting it off. I have about 70 apps on the phone, but not all apps have the option to shut off background refresh in their settings; I don't know if that means that apps that don't have that option don't use data in the background.
I also know, with iOS 9, I can double-click the home button to activate the application switcher and then I can remove apps from running in the background by swiping up.
But I'm still worried that the iPhone will somehow be using cellular data from apps other than the Google Voice app,.
So my questions are: if I've shut off background refresh from all apps with that option, other than Google Voice, AND I remove all other apps from the application switcher, will Google Voice be the only app using cellular data? Or will there be other apps or iPhone processes that will use cellular data too?