Yeah, domain reputation works more or less just like IP reputation for a lot of email providers. Holding onto the domain for a long time and sending some amount

Yeah, domain reputation works more or less just like IP reputation for a lot of email providers. Holding onto the domain for a long time and sending some amount of email from it will help it get "known good" scores with the big providers. I would also recommend setting up DMARC reports because I've heard anecdotes (no evidence here!) that some providers give a positive bump to email from domains they can successfully return DMARC results to... and it'll at least make sure you know if you have an SPF/DKIM setup problem, especially if it's somehow a transient or subtle one (I've had this happen with config mistakes where not all outbound email was being handed to opendkim).