can I ask how often everyone charges their ipad air ? Since I suffered a prolapsed disc last July I have found sitting at my iMac for any length of time very uncomfortable, so I'm using my ipad air rather a lot, and for quite a few hours a day. Just basic surfing and movies etc. I'm also charging it rather a lot, usually each day when the battery gets below about 15%. Will this constant use and recharging do it any harm in the long term ? Thanks for any help.