When our target group is precisely defined and we know its volume, in such cases we should use one-time sendings. Their main advantage is that we can schedule their shipment in advance, which will cause the shipment itself to be calculated much faster in the system and the time from sending to delivery is significantly shorter than scenario sendings. It should be remembered that practically every shipment has a different personalization and unique data for the contact is taken for each shipment, which causes each shipment to be prepared separately for the contacts.
Scenario sendings and scenarios themselves are a good choice when contacts fall into a particular process on a day-to-day basis. When a relatively small volume of contacts falls into a scenario and the prepared shipment does not affect the shipping or delivery time to the user. An example of this may be the process of welcoming users to the site after registration, where the scenario constantly checks if a new contact has registered and if such a contact has appeared, it sends an appropriate email.