Okay this will be my last battery question.... I hope. There might be threads regarding the battery and when to charge, but am wondering whether this is a good rule of thumb. From 100% use my iPad. When it gets to 15% charge it, not necessarily to 100%, but never letting it deplete to less than 15%. So basically charge it as and when but not lower than 15%. And then once a month, deplete the battery completely and do a full charge to calibrate the battery percentage?