What is the minimum daily email sending volume per mailbox and overall needed to effectively scale my cold email outreach, and how can I best leverage my current setup of eight mailboxes to reach 500–1,000 emails per day?
You cannot exceed about 30 emails per mailbox per day due to provider limits. To send 500 emails daily, divide 500 by 30, which gives roughly 16–17 mailboxes; you’re already using 18, so you can reach 540 emails per day. Therefore, the minimum per‑mailbox volume is 30 emails, and the overall capacity scales linearly with the number of mailboxes (mailboxes × 30). Your current results—236 emails sent, a ~2.6% reply rate (~six replies) and one meeting—are promising; scaling that volume will yield proportionally more replies and meetings.