if my MBA is charged from 0% to 100% every single day, how long will it last? my previous laptop, a HP Envy, lasted less than 16 months before I had to but a new battery. It was used several hours daily for work and other stuff. I anticipate the same amount of usage for my new MBA. If the battery goes kaput before the 1-year warranty ends, will Apple replace it? (or within the 3-year AppleCare plan?) Thanks!