Backing up your WordPress site is something you need to pay attention to and not just blow it off. Remember, there is no copy of your web site on your computer. If your site is hacked or in any way compromised a backup will be the only way your site can be restored.
BackWPup is one of the many plugins you can use to make a copy of your site (a backup) automatically.
This plugin does not require a lot of special configuration to make it work.
Always have 2 locations where the backup (it can be a .zip file) will be stored.