I've got an iPad 2 and never have run it down to "empty." Been searching around for what others recommend and find conflicting ideas. The first link suggests running the battery down completely until shutdown every so often and the second link warns against running down the battery any lower than 15%.
How to Calibrate Your Mac, iPhone, or iPad Battery | MacBlend
Prolong battery lifespan for iPad / iPad 2 / iPad 3: charging tips - The how to..
Is any battery maintenance necessary on Apple's devices?
How to Calibrate Your Mac, iPhone, or iPad Battery | MacBlend
Prolong battery lifespan for iPad / iPad 2 / iPad 3: charging tips - The how to..
Is any battery maintenance necessary on Apple's devices?