If you don’t want to send 2 e-mails with Offers to the customer who has made, for instance, 2 orders during some period of time and you want just to send only 1 e-mail.
For instance, on the settings of email template you have indicated for the field Sending time after the order the value Through 7 days. The customer has made 1 order at first and then via 3 days the second one. If meanwhile you have marked the checkbox Do not send notification if the customer has ordered later, then to the customer will be sent 1 e-mail with Offers after 7 days from the moment of the 2nd order.