My 2011 MBA is reaching the end of its second year, and right now the battery health is at 80% (20% wear) with 341 cycles. Battery life started out at around 5-6 hours in Lion 10.7.2 and dropped to around 3-4 hours in 10.7.5 before upgrading to Mavericks 10.9, which did help with the battery situation. According to Apple, they offer a battery replacement program: http://www.apple.com/batteries/replacements.html They seem to be a bit vague about battery wear vs defective battery, because a worn-out battery isn't exactly a defective battery. My MBA is covered by a 3 year AppleCare plan. Can I ask Apple to replace my battery in my MBA before the warranty expires?