Well, even after setting my iPhone 4S up as a new iPhone, it still lags enough to be annoying with almost every operation. I had used it as my "home iPhone" and my 5s as the phone I take with me when I go out. This meant I didn't have to charge my 5s as often. As for my iPad Air, I'm not using it nearly as much as I thought I would when I bought it in 2013. I'm thinking about trading it in for a iPad mini 4 and with the iPhone 6s I plan to get later this year, I'll have a good mobile tech combo once again for home/outside.