The following applies to our Corporate and Business hosting plans.
Clients are able to monitor how much Website and Email diskspace they are using from inside their hosting control panel. Website storage sizes can be found under the 'Websites' section of the control panel. Total email storage sizes can be found in the 'Email' section of the control panel, under 'Mail Disk Usage' . (This is a tutorial on how you access your Mail Disk Usage)
Bandwidth usage can be found inside their website Statistics using the Webalizer Log Analyser (this is a tutorial on how you access statistics). Webalizer Log Analyser will have a daily breakdown of website usage, as well as totals for the previous months going back 12 months, and clients will be able to extrapolate from that, what their monthly usage may be.
All usage calculations and statistics are generated once a day, so reducing your diskspace usage won't show up until the next day.