When you start thinking about scale, the problem isn’t software or copy. It’s inbox math. I approach cold email the same way I approach infrastructure - conservatively and predictably. Personally, I try to keep cold sends under 20 emails per inbox per day. Even though an inbox can technically handle more, I’d rather protect deliverability than squeeze volume. Here’s how scaling really works. Each mailbox is an independent sender. That’s the unit you scale with. • One mailbox → safe at ≤20 cold emails/day • Cost per mailbox → around $3/month From there, volume is just multiplication: • 1,000 emails/day → ~50 mailboxes • 10,000 emails/day → ~500 mailboxes • 100,000 emails/day → ~5,000 mailboxes Yes - that means serious inbox infrastructure. Across our companies, we run tens of thousands of mailboxes and spend five figures every month just maintaining sender health. That’s not waste. That’s the cost of staying in the inbox. The biggest beginner mistake I see is trying to “optimize” by sending more per mailbox - 70, 80, 100 emails/day. Increasing daily volume per inbox feels efficient short term, but it’s the fastest way to end up in spam. The rule is simple: Never scale vertically. Scale horizontally. More inboxes. Same safe volume. Stable deliverability. That’s the difference between campaigns that last weeks and systems that run for years. Comment “Setup” if you want this handled properly.