Is a Nudge Schedule required for only one occurrence in Journeys?

Summary:

We will have Journeys that are auto assigned upon hire and we want to send one (1) reminder if the Journey is not completed three (3) days after it has been allocated.

When configuring the Nudge Type, it asks "Number of Days After Journey is Assigned". If we enter "3" here, will the nudge be sent out three (3) days after the Journey has been allocated or do we have to also create a schedule? Due to these Journeys being auto assigned, we would have to constantly be updating the schedule since it requires dates and employees will be hired all throughout the year.