Keep authentication with the owner
Know who manages the sending domain and who is allowed to change its records. Review SPF, DKIM, and DMARC with that person. A draft record is not proof that a domain is correctly configured, and an authentication pass is not an inbox-placement guarantee.
Keep uncertain contacts separate
A list can contain malformed, duplicated, outdated, or unresolved addresses. Record the source and check date, and preserve exclusions independently of technical validity. Treat an unknown result as uncertainty to review, rather than silently promoting it to a verified contact.
Change the pace deliberately
Review the account history, provider requirements, and total sending workload before raising activity. Define who will investigate an unusual bounce or complaint pattern and when the campaign should pause. Keep the reason for a change with the account.
Use tests as a comparison
Placement tests can help identify a problem in a particular sender and message combination. Record the conditions and compare one change at a time. A sample result cannot describe every recipient’s inbox or guarantee a future campaign’s outcome.