A backup is a copy of a site which is kept on a different server and could be restored if something goes wrong with the live site - an unsuccessful script update, an unintended deletion of some file or of the whole database, etcetera. Restoring the site the way it was shall remove or decrease the damage the problem may have caused, that's by all means a certainly better alternative than having to rebuild your entire site from scratch. Although you could download a copy of your content on your PC, keeping a backup is a functionality that nearly all web hosting companies incorporate as part of their packages. It's important to take a look at how frequently they do that, though, because some companies create a backup only once every few days, that could be far from enough for a booking Internet site or an e-commerce portal in which the information is updated each day. Make sure that you see how easily a backup may be restored, which can be critical if some problem appears on your site.
