The last two posts were about dragging a self-hosted sending domain to the inbox. Auth first, then the slow warm-up. Mine got there, and it stayed there for a good while. Postmaster Tools said High, campaigns landed, I stopped thinking about it.
Then months later placement started slipping on a list I had barely touched. Same auth records, same IP, same warm domain that had been fine all spring. Nothing in my setup had changed. The thing rotting underneath was the list itself, and it had been rotting quietly the whole time.
It took me too long to accept this. A list is not a static asset you clean once. It decays on its own whether you send to it or not, because the people on it change jobs, abandon inboxes, and mistype their address the day they signed up. Leave it alone for six months and a chunk of it is already dead. You just can't see which chunk until it starts costing you.
Not every bounce means the same thing
A bounce isn't one thing. It's a category, and the categories don't all behave the same.
