[khorne]

Note that this checklist seems mostly aimed at people that send email professionally. Parts of it surely apply to individuals hosting their own email, volumes likely do not though.

[2000UltraDeluxe]

The checklist seems to be for businesses sending newsletters and so on. Ramping up slowly is still a thing, though.

[ismaelyws]

Yes mostly for businesses sending newsletters or cold outreach. But parts of it also important for transactional emails (SPF, DKIM, DMARC, etc)