My 5th gen has started acting up lately. It will shut off (battery completely drained would be my assumption), but when I plug it in it fires up with about 60% battery life. When not plugged in the battery drains pretty quickly. It's mainly for playing music in my car, but I have been relying on it to use certain retail apps since I currently don't have a cell phone.
Anyway, my issue is with the "back" button in apps. It will become totally nonresponsive and I have to mash on it like 10 times or so to finally get it to work. I have it on 9.3.5, which is the last version of iOS 9 that has been released for the touch. I have not tried to restore it because I have like 45gb of music and that would take forever. Maybe there is some issue with nonresponsive parts of screens, I really don't know.