If you run a website, having a backup is something very necessary, specifically if you have important info or you have invested time and cash in creating the site. There are numerous situations why you could need a backup - if you update a script and something goes wrong, if you delete a file or a whole folder unintentionally, 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 every now and then, but due to the fact that you simply can't do that after each change, you need to rely on the backups which your web hosting provider generates. Since that is something really vital, you need to make sure that they keep up-to-date backups, because a backup generated once every one or two weeks may not do any good if you run an Internet site such as an online store or an accommodation reservation portal.