Hi, tomorrow I get my iPad, but one question: Do I have to calibrate my iPad's battery (like MB's), or not. So do I, during first use, have to use the iPad untill the battery is empty, and then have to charge it full, or don't I have to do that. And how do I have to use the battery. Just charge it when it's possible, and do. Or doesn't the battery-life never gets worser?