Shared vs dedicated IP
Whether your mail leaves on an address shared with other senders, which is the default, or one only you use.
Say it out loud
“Almost everyone sends from a shared address the platform manages. Our own only helps above real volume, and it has to be warmed first.”
On a shared IP your mail leaves alongside other customers of the same platform, and the platform manages who it lets in. On a dedicated IP your traffic alone shapes the reputation: no bad neighbours, and no borrowed goodwill either, because you start from no history at all. Shared is the right answer for most senders and the one you already have unless somebody deliberately changed it.
Every mainstream platform puts you on a shared pool by default. If nobody has told you otherwise, this is you.
This is the fear people cite. In practice mainstream platforms suspend bad senders faster than you would notice them.
A dedicated IP that sends twice a month has no reputation, only a gap. There is no published threshold and we are not inventing one.
Shared is not the beginner option. It is the correct option until your own volume is steady enough to say something about you.
Part yours
The platform does part; the rest is genuinely yours.
What goes wrong
Moving to a dedicated IP to fix a spam-folder problem. It does the opposite at first: you have discarded the shared pool's accumulated goodwill and replaced it with an address nobody has ever seen, while the actual cause — usually list quality — is untouched.
What people get told
The claim. “A dedicated IP improves deliverability.”
Actually. It gives you control over your reputation, which is not the same as a better one. Below steady volume it is strictly worse, because there is not enough traffic for a provider to form an opinion, and an address with no opinion attached gets the benefit of no doubt.
See also
Where this sits
Stop 3, it leaves your building. Your platform hands the message to a mail server, which stamps it with proof of who sent it.