I leave my phone in airplane mode most of the day and only use 4g in emergencies. I have e-books and podcasts downloaded, but the interactive stuff like forums I only do when I have wi-fi. This means when I'm out and about I'm off wifi and only listening to podcasts or reading ebooks at least. If someone wants to call me when I'm out of the office, they can schedule a call. Picking up the phone is annoying because I get a couple of spam calls a day.