I've found that the upper limit of MBA battery life depends a lot on how heavily you're using it. I stopped worrying about my devices running out of juice on t

I've found that the upper limit of MBA battery life depends a lot on how heavily you're using it. I stopped worrying about my devices running out of juice on the move by packing one of these in the backpack : http://www.hypershop.com/HyperJuice/External-Battery-for-MacBook-iPad-iPhone-USB-100Wh/MBP1-5-100-BOX.html http://www.hypershop.com/HyperJuice/External-Battery-for-Mac... At first, it seems like a little bit of extra weight to carry around, but you stop noticing after a short time.