I don't know if anyone else had this problem, but I use my Pi in a few different locations, and changing wifi details can be a pain - especially if you're in a new location and can't plug an Ethernet cable in.
I threw together a simple tool that allows you to set the SSID and PSK over bluetooth. It's super basic at the moment - you need to have already paired your handset with your Pi - and I've written a basic Android app. Still, thought it might be useful/interesting for anyone here.
Python script to run on your Pi - https://github.com/brendan-myers/rpi3-wifi-conf
Android app (use Android Studio to build) - https://github.com/brendan-myers/rpi3-wifi-conf-android
Would be cool to hear what everyone thinks (improvements etc)