> First, if anyone was doing anything for 12 hours a day, it's probably an issue. A good yardstick, but it depends on the activity. 12 hours on SnapChat daily

> First, if anyone was doing anything for 12 hours a day, it's probably an issue. A good yardstick, but it depends on the activity. 12 hours on SnapChat daily => probably excessive. There are days when I have hiked 12 hours a day (definitely excessive!). The difficulty with a phone is the myriad uses a phone has in our lives. GPS-mapping (not just for driving, cycling or walking, but for hiking too - e.g. alltrails.com), star-gazing/charting at night, creative writing, recording/listening to music, programming (yeah using ssh apps), photography, video, email, texting, audiobooks (as a traveling executive, I often drive 5+ hours using G-Maps, while I am listening to an audiobook, while I get interrupted with dozens of phone calls), health/fitness/workout monitoring, sleep apps, games, banking/finance/credit, monitoring my home/AirBnB's etc, boarding passes, Uber, shopping, way too many hours on HN, you get the idea. As has been said, we are cybernetic organisms, and the mobile phone is an extension of us (soon one day inside us). Whether we use it to enrich the diversity of our lives or to dumb-down and become mono-active, I think that is the issue.