I do it almost every day for my database based websites and for static ones I normally edit/create pages offline and only then I upload them to the server, this way I have an offline copy of all of the stuff.
My suggestion would be to take a backup of your database sites ASAP; you should never trust your host with your data. If by any chance there is a problem with the server then you might just loose all the data you have worked so hard to create.
I backup mine every weekend, although I do forget the odd time. It's always good to have that sense of security that if anything messes up, you have your back up.
I back up if and when the need arises. My site contents are not updated regularly. Besides I make a copy of my contents using my local PC before I upload them into my web site.
Well i do every 2 to 3 days and when i am installing a modification or a module because if something goes wrong i can restore it.Also if some hacks my site then i can restore it.
I don't need to do on weekly bases as my hosts does on weekly bases.
On my main website i make an automatic backup each day for my database - if something goes wrong, it will be easily restored.
I recommend everyone doing so, as you never know what can happen!
i have a small forum site..so i dont care to take backups..but if i had a huge site..then i wouldnt sleep without backing up because you can never be sure..anything can happen..like some issue with the datacenter or the like..its always best to backup...
I do backup daily.
I've got the wp-backup plugin for my wordpress site. It does a backup and mails to my gmail account automatically everyday.
So i am safe.
I only do mine about once a week. I know... I should do it a bit more often but there is sooo much to update. I wish I just had a Wordpress blog but I have quite a few websites!