so I have unlimited data and dont want to change my plan, but my wife has a 2gb data plan for $25 and I called att today and they said to use hotspot she has to upgrade to the 5gb plan which is for $50 with discount comes to around $39. that will be an increase of $14 or so which we don't mind. what they also said that my wife cant revert back to the 2gb once upgraded. What I want tp know like the OP how much battery will be drained phone the iphone in case there is no charging option. Can you watch a moveis on netflix with tethering? will we be able to use the ipad and its maps as a navigation device while on the road by tethering the iphone as a hotspot. Or for maps and navigation one needs a cellular ipad. kindly suggest if changing my wifes data plan would be a good move or not.