Hi Everyone, I'm having a hard time getting a definitive answer to this question. I have a 13" black MacBook purchased within the last year or year and a half. I just got a second battery that I want to use on a trip on Thursday (long flight). I can't find an answer on apple.com as to whether I need to calibrate this battery during its first use, as you used to have to do for some apple notebooks, or during the first week, as for others, or just should do it once in a while but don't have to do it right away. Does anyone know the answer? Thanks!