A backup is a copy of a website that is kept on an independent hosting server and can be restored if something goes wrong with the live website - an unsuccessful script update, an unintentional deletion of a file or of your entire database, etcetera. Restoring the Internet site the way it was will remove or decrease the damage the problem may have caused, that is by all means a much better alternative than having to rebuild your whole Internet site from scratch. Even though you may download a copy of your content on your laptop or computer, keeping a backup is a functionality that most website hosting providers offer as part of their plans. You must check how often they do that, though, because some service providers generate a backup only once every week, which can be far from enough for a booking site or an e-commerce portal where the info is updated each day. It's adviseable to see how fast and easy a backup may be restored, which could be critical if some problem appears on your website.