If you manage a site, having a backup is something rather necessary, specifically if you have important info or you have invested time and money in creating the site. There are numerous scenarios why you may require a backup - if you update a script and something goes completely wrong, if you delete a file or an entire 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 PC occasionally, but as you can't do that after each change, you'll have to rely on the backups which your host company generates. Due to the fact that this is something extremely vital, you must make certain that they keep up-to-date backups, given that a backup generated once every one or two weeks will not do any good if you run a site like an online store or a holiday accommodation booking portal.