Does bluetooth affect battery life? I know the 2011 Air uses bluetooth 4.0 which is supposed to use very little power. I use an external monitor with a wireless keyboard and mouse when at home on my Air in clamshell mode. When I am mobile I tend to turn bluetooth off but I always forget to turn it back on when I get home and pull the air out of its bag and then plug it straight into the monitor, magsafe, and usb speakers. This leads me to open the lid, type in my pass, turn on bluetooth and plug everything back in whenever I do forget to turn on bluetooth. It would be less of a hassle if I just leave bluetooth on (if it has minuscule battery draw) and I can just plug it into my external stuff straight from the bag in sleep mode and just click my trackpad or keyboard to fire it up and the external monitor.