Is it mandatory on the part of your webhost provider to back up your files? I lost my site including my home directory when my host provider moved to a new server. I don't have an updated copy. What is the liability of the host provider here?
Almost every dissent host backs up customers databases and not their files. I don't think i have ever heard of a hosting company that backs up their users files. If the site is imprortant to you a backup should have been downloaded and put it on your local drive and then a disk
If you use cPanel, you can download your own back ups pretty easily. It's always best to make your own rather than depending on your host's back ups. But to answer your question, no, it's not mandatory. If your host doesn't offer at least weekly back ups, I would suggest you find a host that does.
No way should you ever rely on your host for backups. ALWAYS keep your own backups if you value your data - it's just totally lazy not to.