Dedicated IP or Shared: The Decision That Actually Depends on Your Volume

Every ESP offers a dedicated IP as an upgrade, and the pitch is straightforward: your own reputation, not shared with strangers. What the pitch skips is that a dedicated IP starts with zero reputation and no track record at all - and building one badly is worse than never having had it.

The volume line

Below roughly 50,000 emails a month, a shared IP is almost always the better choice. An established shared pool already carries a reputation built from thousands of other senders' good behavior, and you inherit it immediately - no warm-up, no ramp, sending from day one at whatever volume you need. A dedicated IP only starts earning that same trust once you do the work yourself.

Above roughly 100,000 emails a month, the case flips. At that volume you're big enough to build - and control - a reputation entirely your own, without a noisy neighbor's bad list dragging your inbox placement down with it. The number isn't a hard cutoff so much as the point where the tradeoff stops favoring shared.

The part the volume threshold doesn't cover: consistency

A dedicated IP needs to send meaningful volume on a regular cadence - roughly 3-4 days a week at minimum - to hold the reputation it built. Mailbox providers read a long gap in sending the same way they read a brand-new IP: no recent track record, treat it cautiously. A dedicated IP that goes quiet for a month effectively needs re-warming.

If your sending is seasonal, irregular, or you can't commit to a steady cadence, a dedicated IP is a liability even at high volume - the pool's aggregate consistency is exactly what you'd be giving up.

What actually goes wrong

• Moving to a dedicated IP and sending full volume immediately - the single most common mistake, and the one that produces the worst outcome: a brand-new IP with no reputation, hit with the same volume a warmed one would carry
• Warming up, then going quiet for weeks between campaigns and wondering why placement degraded
• Splitting volume across several dedicated IPs before any of them has enough send history to matter - diluting the exact thing a dedicated IP is supposed to build
• Assuming a dedicated IP means less monitoring, when it actually needs more: nothing is absorbing a bad list or a spike except your own reputation

None of this is a reason to avoid dedicated IPs - at real scale they're the right infrastructure. It's a reason to treat the switch as what it is: trading an inherited reputation for one you now have to build and maintain yourself.

Check the domain (and once you have one, the dedicated IP) against the major blacklists