My Pebble, which uses some internet-based watchfaces, such as those that get the weather, don't seem to effect my data usage at all every month. Maybe 50 extra megabytes, give or take. Lengthening the intervals that apps refresh at in the background really helps as well.
The watch will connect to a wifi router, and from there to a phone on the same router. Also, if away from the phone but on a router that it knows about, it can also do some simple internet activities like iMessaging.
The watch will connect to a wifi router, and from there to a phone on the same router. Also, if away from the phone but on a router that it knows about, it can also do some simple internet activities like iMessaging.
It connects to the iPhone directly via Bluetooth, but if the iPhone isn't in the short Bluetooth range, then they can connect via Wifi using a router. Apple said this was so that when you are at home, you don't need to carry your phone wherever you go.