I am trying to identify what would be the best practice for mailbox size limitations. Microsoft is very vague on this point and I repeatedly see posts stating "it depends on server hardware, desired backup/restore windows, server utilization, etc." I need a figure for our CIO to recommend for approval so we can finally lock down exponential growth on our mail system and "it depends" won't resonate. Are there ANY hard and fast rules/guidelines? I see a size limit >2 GB cannot be setup via the GUI. I see pst files and ost files with 2 GB limits. Is 2 GB reasonable? Opinions and personal experience are as welcome as hard facts. Thank you!