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some provide non and you are required to backup your own site.
most will provide backups though, some monthly. majority of good ones will backup weekly.
and some really really good hosts will backup daily.
some say they do daily backups aswell, but have noticed and experienced in the past that when the crunch came, they only had backups from a week ago..
it is of course still wise to conduct your own backups aswell for obvious reasons..
mysql dumps and files alike..
ftpsync software can synchronise your server to your pc.. that way only newer files or edited files will be transferred so you don't have to keep downloading everything all at once.. ok the initial sync can take a few hours if you have lots of files but it's well worth it..