My 'dumb' phone lasts 25 days on battery.
The decision was a combination of a lot of things- I save money. I am aware of my surroundings. I think. A lot. Sometimes I talk to people on the train. Or I will print out a paper and not bring anything else with me. "You read this you lazy no-attention mfucka or you sit here and do nothing". I am learning to draw- also on paper. I do not care which wireless company has been revealed this week to have a direct back door for the NSA. No one ever calls me. This is a big deal for me. Even when I had a phone, there is rarely necessity or cause for disruptive synchronous communication.
And, for everything I miss about phone ownership, there is almost always something good that came out of it. I miss maps. But I also never learned where anything was. I always depended on my phone even after living in a city for years.
I miss being able to immediately find the results to some shitty singing compeition show. Others miss me being more responsive- my response time is now ~5-10 minutes during the work day but on the weekend it might be a few hours. But really, its ok.
I would consider a really nice dumb device though.