Mailbox rotation capacity planning: budget eligible accounts and follow-ups

Define the decision

A connected account may still be unavailable because of policy, daily usage, warmup activity or receiving failures. Campaign selection also matters: an unused connected mailbox does not automatically increase a campaign’s capacity.

Work through the procedure

1. List mailboxes selected for the campaign and verify each send-and-reply path.
2. Record application limits and known external traffic.
3. Reserve capacity for due follow-ups and ordinary replies.
4. Exclude failed or restricted accounts from the plan.
5. Review capacity again when account selection or provider conditions change.

Worked example

The following is a synthetic example for this procedure, not a customer result or performance benchmark.

Connected accounts: five
Selected for campaign: three
One selected account has unresolved receiving failure
Planning basis: only verified eligible accounts, with follow-up demand reserved
Five multiplied by a nominal cap would overstate usable capacity

Read the result

The plan should explain why each mailbox is included. Adding accounts cannot solve a campaign-level scheduling problem or make an irrelevant audience appropriate.

Check before moving on

1. Check recipient timezone and sending window separately.
2. Keep suppression consistent across all selected mailboxes.

Limits and next action

Do not rotate accounts to bypass provider restrictions or recipient objections. Treat capacity as a constraint on a reviewed outreach plan, not a target to fill.

Source: Zintara campaign capacity context