I finally got my MBA today and I couldn't be happier with it! It was (fully?) charged when I used it for the first time, and I didn't bother plugging the charger in. I kept using it until I got the message that the computer was running on reserve battery and kept using it until it automatically went to sleep and 0% as I thought this was necessary the first time. Now it's in that mode on my bed and i'm thinking of leaving it like that until morning when I will fully charge it and use it as usual. But I just read that this procedure isnt necessary on the new macbooks, so am i in some way harming the battery? Will this count as a calibration even though i'm not sure the battery was 100% charged before I ran it down? Should i keep it in sleep mode for 5 hours before charging it for the first time OR plug it in right away? Sorry for my paranoia, I just want to know that i'm not doing anything wrong.