Backup - The other things forgotten

So I use the Full Backup that is defined in FreePBX 13.

What I want to know is what other things should I be backing up besides that?

So far, I have these directories:

1. /etc/asterisk/keys              Keys!
2. /etc/asterisk/digium_phones     Digium Phone stuff like contact book, custom images
3. /var/lib/asterisk/licenses      Asterisk DPMA, Fax and G729 licenses. 

Any other tips or guidance as to what else I would need to backup beyond the built-in full backup template included with FreePBX 13 would be appreciated.