At least my smartphone built-in stats app shows that my sync-everything-everywhere habits (both mobile data and wifi) cause just 20% of my battery drain, and more than half is spent by the screen which is used for much, much shorter periods.
Sending a few bytes doesn't take much juice at all, and the phone radio is anyway communicating with the cell tower very often to "check in".
Sending a few bytes doesn't take much juice at all, and the phone radio is anyway communicating with the cell tower very often to "check in".