For some unknown reason Scrabble recommends that you turn WiFi off and BlueTooth on to play multiplayer w/ an iPad as the board. It's an odd request but I do it anyway.
When I leave the office my iPhone can see the office base station even when I'm kitty-corner waiting for the bus, but the signal isn't strong enough to work so I have to turn WiFi off.
In order to check my wireless usage w/ Rogers' iPhone app they require me to be on 3G. It's lame but that's how they roll so I have to go along with it.
Sometimes once it's off I forget about it because I have a 6G data plan which I haven't been able to burn up even using Grooveshark for a couple of hours a day. Then if I want to do something on a LAN at home or work I need to turn WiFi on.
I leave 3G and BlueTooth on all the time. Some of my friends turn BT off when they're not using it and I try not to hassle them about it. It doesn't wear your battery down unless you're using, in my experience anyway. So less savvy users want to do this kind of thing too, not just us nerds. :)
