I feel like I've stepped back in time! Battery technology has changed. You do not need to let the battery in the iPad run right down. You can trickle charge it, often and in little amounts if that's what you like, and it will provide the longest life. Older batteries needed to be drained once in a while and get a full charge. Little and often is the best now. So just use it whenever you want and when you can. Not only will it do no harm, but you will get the longest life possible from the battery. Amazing that some people still give out advice on dated technology.