I always left my wifi, mobile data, pretty much everything else on all the times. I noticed when I left wifi range and mobile data should take over. In most case it did. But often time, it didn't. When it didn't, I have to shut off mobile data and re-enable it to establish connection. Did anyone see this problem? I also saw where both wifi and mobile data are on at the same time for good 5, 10 min at time.