I've read and heard many times that to save battery on your phone, use wifi and turn off mobile data (3g/4g) when you can... I'm stumped as to how this saves battery power though? Wifi, though much closer to it's transmitter, is ALWAYS transmitting where 3g/4g, though much farther from their transmitters/towers (whatever, you know what I mean), only transmit as needed. Right? If that's the case, then it seems like the two would be a break even? Only time it seems that wifi would conserve battery is during times when you're constantly & actively transferring data (streaming a movie, music, downloading etc). What am I missing here?