Website backups are more than just an element of best practices, they are essential!
If for any reason your website goes awry the option of restoring it from a recent backup is often the best solution, and sometimes it is the only one available. To create a complete backup the database and the custom files will both need to be backed up. An automatic backup strategy is easy to implement using the Backup & Migrate module, and a manual backup can be created before major updates or new implementations, providing a convenient restore point taken immediately prior to the changes going in.
Backup & Migrate
The Backup & Migrate module facilitates emergency recovery and site migration. You can configure it for automatic backups saved to the filesystem - with more frequent backups during development.
You can also create a manual backup before undertaking any complex configuration. That way, you have a "restore point" in case of disaster.
While there may be some issues of security when you save the database and content as a file (you could exclude certain tables, perhaps), the benefits of having a rollback in case of disaster are significant.