Email Storage
Cost Tools

When you hit Send, the mail server creates a separate copy in each recipient's mailbox. Sending to 50 people stores 50 copies. Distribution lists hide this — a single address can represent hundreds of mailboxes behind the scenes.

Most email clients include the full prior thread in every reply. A 5-reply chain on a 25 MB attachment stores roughly 5× the original — per recipient, per backup copy, per geo-region.

HIPAA: 3–6 years. SOX/SEC: 7 years. CMMC L2 audit records: 3 years. FAR/DFARS: 3–10 years by record type. Legal holds freeze data indefinitely. The cost clock runs whether the message is ever read again.

AWS GovCloud, Azure GCC High, DoD IL4/5 carry storage premiums of 25–175% above commercial rates. Every retained byte — for the full retention window — at the sovereign-tier price.

EOA (~$3.50/user/mo) adds unlimited auto-expanding archive to E1 and Exchange Online Plan 1 licenses. E3 and E5 include it. Archive items are moved by retention policies and no longer count against the 50 GB primary limit — but policies must be configured to actually work.

Platforms like AvePoint Cloud Backup charge a per-user flat fee (~$2–5/user/mo) covering backup storage for Exchange, SharePoint, Teams, and OneDrive. The flat rate undercuts Azure blob pricing once a user's backed-up data exceeds roughly 5–8 GB/month, and adds point-in-time restore that native retention policies don't provide.

Backups older than 90 days are typically write-once, read-rarely — Cool saves ~44% vs. Hot. Files beyond 1 year that you'll rarely retrieve are Archive candidates at ~95% savings. The tier comparison in the results shows the exact dollar difference for your current configuration.

For M365 workloads, platforms like AvePoint offer per-user flat fees that include SharePoint, OneDrive, and Teams backup storage. Breakeven against Azure Blob Hot is roughly 5–8 GB/user-month — and significantly sooner in GCC High or DoD environments where blob premiums apply.