Your daily disk space usage is recorded. At the end of each calendar
month, the month's data is collected, the highest value is dropped, and the remaining
days are averaged. If your average is then over the limits on your account, an
additional charge will appear on your next bill. In most cases disk space will not vary considerably unless you also have an anonymous FTP site, are receiving huge files via e-mail, or are allowing e-mail to accumulate on the server.