Backup
As with anything where you spend a lot of time setting it up, it's always a good idea to do periodic backups of your XBMC settings and library. This is especially true if you are thinking of running a development build such as a nightly, monthly, or beta. There are various ways to backup XBMC's settings, the easiest simply being to make a copy of your userdata folder, but this page will attempt to consolidate the different methods and explain them.
What settings XBMC uses and where are they stored
Nearly all of Kodi's settings are stored in the userdata folder. Some files, such as add-ons that are not included by default, are stored in the parent folder to userdata, the XBMC folder Template:Helix note.
Backup add-on
The community XBMC Backup add-on is a great way to backup all of your Kodi settings, add-ons, and other related files. It includes options such as automatic scheduled backups, backing up to cloud storage such as Dropbox, and configuring custom backup directories.
Manual backup
Backing up the video library
Watch status only
These add-ons can be used to backup or even sync your watched status for videos in your library:
System backups, RAID, and other generally good ideas