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 (http://www.macblend.com/how-to-calibrate-your-mac-iphone-or-ipad-battery/)
Prolong battery lifespan for iPad / iPad 2 / iPad 3: charging tips - The how to.. (http://thehowto.wikidot.com/prolong-battery-lifespan-for-ipad)

Is any battery maintenance necessary on Apple's devices?

At the beginning yes I believe - condition the battery by running to zero then full charge twice is what I usually do on a new device.

I will say you to go for discharge your ipad every week till 10% battery. I think its mid way to do something with no risk for longer battery life.

My 14 month old iPad 2 has never been run below 25% and is plugged in to the charge cord every single night regardless of the battery level without any ill effect. I still get over eight hours with around 25% left.