You have a lot of important stuff on your website which means you have loads of important data stored on your host's server machine. But one fine day you just wake up and find that all your data is gone.
Your website is no longer there. Maybe the server hard disk crashed. May be the hosting company went out of business all of a sudden or took your cash and data and made of. Or a hacker compromised your account and deleted all your files. Unless you had a proper backup of your website, you will be in an extremely pathetic situation because you lose all your data which is irretrievable and your website disappears overnight leaving you in a soup. Maintaining backups will cost money and time which is why individuals as well as companies don't bother to do it.
But they don't realize how well a savior a backup can be when such situations as described arise. It can minimize risk to a large extent. Depending on the type of site that you run, you will need to choose a backup option that fits your needs. If you run a forum, news site, or any other site with current information you will want a daily backup, at the very least. However, if you operate a simple personal page, that has not changed in over a year, just backing up recent changes is ok.. It's best if the casual webmaster backs up every week or so.
Create a separate Web Backup folder on your own computer. Then simply download all your files on the server to this folder by using any FTP program by copying your main folder to your local hard drive. This is the easiest way to maintain a backup.