Editing Prevent contacts from entering my automation twice (section)

== Common Use Cases with Examples ==
- **Scenario 1:** You have an automation for a welcome email series that is activated when a contact subscribes to your mailing list. By setting this to allow entry '''Only once''', you prevent a contact who may subscribe multiple times from receiving 3 different welcome emails.
- **Scenario 2:** If a contact is going through a re-engagement campaign and they have already completed the campaign, they will not receive the emails again, ensuring a better management of your contact lists and resources.