I was wondering what you do with your old smartphones once done with them? Do you dispose of them? Do you find some place to trade them in? What about in cases where the phone is still worth something if you can find a specific person wanting a used phone of that carrier / model / etc?
Before you dispose of a smart phone? Make certain you have done a factory reset. Just to protect yourself.
Then? There are usually charities that can re-distribute old, working phones to battered women's shelters. You need the phone, and one charger. All modern phones-- if they are new enough to work in existing networks (i.e. GSM) then they are by law, required to work as a 911 access point.
Thus, a woman who is fleeing an abusive situation, and is without a phone of her own, may have an emergency contact method she can carry.
Or? Most local Target store has a "recycle phones" box-- since all are now glued shut, to recycle the battery they must be destroyed to get at the battery.
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Finally, there are lots of useful things to do with old smartphones. I have a Moto G, that I keep in the car, as an MP3 player, and an Audible book device. It's connected to a car charger, and uses it's bluetooth to feed the stereo. My Moto G sports a micro slot, so there's plenty of room for my MP3 collection.
I could also use it as a Kindle reader.
It won't dial ordinary telephones, and it won't to text messenger. But Google Play works fine over WiFi. And Audible seems to work equally well, again over WiFi.
As for a music player? Since all the MP3s are local, it does that quite well.