Should outbound go on the main brand domain at all?

For most B2B teams above small volume, no. Use a cousin domain for cold outbound and reserve the main brand for transactional and client email.

How long does a new domain take to warm?

Two to four weeks for most B2B patterns. Start at 20 to 50 sends per day, ramp gradually, aim for high early reply rates.

Yes. Every sending domain needs its own authentication setup. Reputation is per-domain; authentication must also be per-domain.

Either park it for 3 to 6 months and re-warm, or retire it permanently. Re-warming only works if the root cause of damage is fixed.

Most B2B teams converge on 2 to 4 sending domains. The right number scales with weekly volume and the team's appetite for operational overhead.

Under 2,000 weekly: 1 to 2 domains. 2,000 to 10,000: 2 to 3. 10,000 to 50,000: 3 to 5. Above 50,000: 5 to 10 with a named owner.

Close cousins of the brand (reach-robin.com, reachrobin.co) read as legitimate. Disposable look-alikes trigger buyer pattern recognition as spam.

Per-domain authentication, volume allocation by reputation strength, shared suppression across all domains, written retirement rule.

Too many domains, disposable look-alikes, no shared suppression, no retirement rule under pressure.