Backup batch

I would like to create a batch file that will beackup indidivual users’ files to a server on a daily basis. Just using the xcopy command will accomplish this, but I’m concerned that if they copy files to the server and the next day they intentionally delete some of these files from their hard drives, the copy of those (now unneeded)files still reside on the server. Eventually I’ll be faced with over burdening the server! Thanks.