First time only for audience emails

Someone joins your "Took the order bump" audience, gets the thank-you, drops out when a refund lands, then buys again and rejoins. Without a rule, they get the same thank-you a second time, and on a busy audience some people bounce in and out every few days.

The enemy is the same email landing twice because someone crossed an audience line again.

Audience emails and automations now have a Who gets it setting. First time only is the default for new automations: each person gets it once, even if they leave the audience and come back. Every time, at most once per N days sends it again when they come back, but never twice within the days you set (1 to 90). There is no unlimited option for anything that sends email. You choose it in the Send an email window on an audience, or on the On Entered Audience and On Left Audience triggers in the builder, next to the holdout.

A few rules keep the numbers honest. Entering and leaving have separate clocks, so a welcome on entry does not block a goodbye on leaving. Going in and out quickly never sends more than the setting allows. People in the holdout count as having had it, so they are not picked again next time. People skipped because they declined consent, unsubscribed or have no email address keep their turn and can still get it later.

On the audience page, an automation row now shows Who gets it and its holdout, with Edit in automation to change them on the trigger. Klaviyo, ActiveCampaign, Mailchimp and webhook actions keep their cooldown there: the same change is not sent to a person again within that many days. Automations you made before today keep working as they did, every time with at most one run per their cooldown, until you switch them.

Try it: go to Reports, then Audiences, open a customer audience, click Add under When people enter or leave, pick Send an email and look under Who gets it.