When you manage a site, having a backup is something very important, especially if you have important data or you have invested money and time in creating the site. There are different situations why you could need a backup - if you update a script and something fails, if you delete a file or an entire folder unintentionally, and so forth. 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'll be able to download a copy of your content on your computer every now and then, but as you cannot do that after every single change, you will need to rely on the backups your web hosting provider generates. Due to the fact that that is something rather crucial, you must make sure that they keep up-to-date backups, since a backup performed once every one or two weeks won't do any good when you run an Internet site such as an online store or an accommodation reservation website.