Which setting(s) would prevent Discourse from emailing an old user?

[watchmanmonitor (Allen Hancock)]

Continuing the discussion from Disable user account and what’s the difference between Suspended and Blocke users?

Which of these options would also prevent them from ever getting an email from something they are Watching or via Mailing list mode?

[jomaxro (Joshua Rosenfeld)]

Blocked will stop mailing list mode, suspended will prevent all emails (except for staff PMs).

See

Understanding user statuses, roles, and permissions

Discourse has many built-in user statuses, roles, and permissions. These statuses and roles can be seen for a given user when viewing their profile from the users’ section of the admin dashboard: [admin-dashboard-user-permissions] The following describes the meaning of each status. Permission Status Activated Account has a verified email and is therefore active in the Discourse instance Account may login to Discourse, inactive accounts may not login Inactive accounts can only verify the…

[fefrei (Felix Freiberger)]

Deactivating will also prevent mails, until the account is active again.
(Therefore, when using SSO, deactivating an account and blocking login on the SSO site will prevent mails indefinitely.)