Juli Clover points to John Siracusa’s review of OS X Mavericks in which John was able to get over 15 hours of battery life on a 13-inch MacBook Air running a light web browsing script. I installed Mavericks on my 2011 11-inch MacBook Air earlier today and the battery life does feel quite a bit better than it did with Mountain Lion. I love when Apple releases new software and all of my old hardware feels new again.