BACK UP ! Bak up ! Back Up !
Always make sure you have a functional, working backup of your Joomla website ! This cannot be stressed enough !
THE component you NEED in any J! installation is Akeeba Backup by Nicholas K. Dionysopoulos.
Akeeba Backup allows you to create automatic backups of your entire site and database.
You can easily restore backups or move your site and so much more.
As most components and plugins, this comes in both a free and a pro edition.
I've used the pro version on all my sites for a couple years now, and it has always worked great ! Also, their support is second to none !