What I look for before replacing anything

You will hear people say cold email domains and mailboxes should be rotated every few months.

I would not use a fixed timeline.

Some mailboxes start losing performance quickly. Others can keep working for months.

What matters is how they compare with the rest of your setup.

1. Find where the drop is coming from

If one mailbox starts getting worse placement or more rejections while the others are fine, start with that mailbox.

If several mailboxes on the same domain get worse together, look at the domain.

If several domains on the same setup start dropping at the same time, look at the provider or IP pool.

A fresh mailbox will not give you a fresh domain reputation. If the domain itself is struggling, adding another mailbox may not fix the problem.

2. Do not wait for a full burn

A mailbox can still be sending and showing strong delivery while inbox placement is already getting worse.

Pull the sender out of the campaign and keep it on premium-pool email warm-up.

If placement comes back, bring it back into the campaign.

If it keeps performing worse than the rest, replace it.

See it in action

I am hosting a live session with Apify on how outbound agencies are generating over $1M in pipeline.

We will walk through the workflows, tools, and automation behind campaigns that actually close.