Dreams of an unfettered existence, with only a landline phone at home, occasionally tempt me to ditch my cellular phone. A phone with nothing more than a keypad paired with an answering machine that records to cassette would be the height of simplicity in today's world.
Idealism aside, a mobile phone makes far more sense than a landline. Cellular phone service benefits from a competitive market. A mobile phone can be extremely useful in emergencies. A smartphone can provide Internet access in most populated areas.
I do not advocate ditching the cell phone, although I do pine for the time when landlines were the norm. Instead, I advocate a middlepath based on a central tenet that one should not use a case for a mobile phone.
Without a case on your phone, you'd be worried about accidental damage to your phone. How does this damage happen? Most likely, you're using your phone while you're distracted. Maybe you're juggling it while carrying groceries, maybe you're driving; the cell phone's ubiquity leads us to use it without being mindful about its use.
Do you have an additional enclosure for your laptop to protect it at all times? A few people do, but most people instead use their computer in a regimented fashion. You keep it in your laptop bag, retrieve it for use, then put it back away. When you have your laptop out, you're careful with it, because you're mindful of using it.
We should treat our cell phone as we do our laptop. We should put our phone away for extended periods, and we should only use it intentionally and mindfully. Ditching the cell phone case forces one to be more careful with one's phone; more mindful of its use.
Of course, if you're working or doing a lot of communication with your phone, you'd want to keep it at hand. At work, keep it at the corner of your desk as you would a landline phone. If you want to check-in on social media regularly, consider a regimen of fifteen minutes every two working hours (0800, 1000, 1300, and 1500, if you work 0800-1700).
Hopefully you can cultivate mindfulness about your use of technology and its impact on your life in your own personal way. If you're struggling to do this, ditching the cell phone case may be a great way to trigger mindfulness when using your phone.