When I got my first Android phone a couple of years ago, I wound up using an app called Writer Plus to keep track of my notes. It is pretty simple, but allows use of folders to keep things organized and some formatting using markdown. I was able to use an app called Dropsync to back up the text files to Dropbox (I think the Dropbox app does this now, but Dropsync works fine).
On Friday, I got a line on the screen of my fairly new phone that wouldn’t go away, and one way to troubleshoot that was to wipe the phone. So I backed up my notes folder to my SD card before wiping, but I forgot to back up my passwords file, an encrypted keepass file. Then of course I needed that file, but it seemed to be gone. That didn’t fix the screen (I hope it’s not from my homemade Clorox wipes), I sent it in under warranty (hopefully the will replace it since the glass cover over the camera is cracked too). I just had to move my SIM card and SD card over to the old phone and I was back in business pretty quickly.
It still bothered me to lose my passwords, so I looked on Dropbox to see if I had put a copy there. It turns out that the keepass file had been stored in my Notes folder which was backed up daily to Dropbox, so I actually had the latest file all along (not sure why the Find feature didn’t work, but maybe I was looking in the wrong place). Pretty clever of me to leave it there where it would be backed up, but it makes sense because I used to keep the passwords in an encrypted note on my iPod Touch, so it was note-related in a sense.