If you manage a site, having a backup is something really necessary, especially if you have important information or you have invested cash and time in building the Internet site. There are different scenarios why you could need a backup - if you update a script and something breaks down, if you erase a file or a whole folder accidentally, etc. Having regular backups will help you avoid any loss of information or at least minimize the damage, which is still better than losing the entire site. You could download a copy of your content on your computer system occasionally, but because you simply can't do that after each change, you have to rely on the backups which your host company generates. Since that's something really important, you need to make certain that they keep up-to-date backups, since a backup performed once every one or two weeks will not do any good when you run a site such as an online store or an accommodation booking website.