Apple has been advertising this 30 days of standby time for years. Has it ever been true? My iPad 1, iPad 3 and iPhone 4 all lose 5-10% per day if I leave them unplugged. Okay, that doesn't bother me. Two weeks ago I left on a 6 day trip and left my 2012 Macbook Air sleeping. It was at 100% when I left and when I got back it was at 10% and the power warning came up. My power settings are as follows: Put hard disk to sleep when possible - on Power nap on battery - off Bluetooth - off To me it doesn't seem possible to get 30 days under any circumstances.