So far, the only type of maintenance sub-periods we've used is one-time maintenance. We decided to call those periods that were configured in a separate tab sub-periods to distinguish them from the main period, configured in the first tab, Maintenance. We also discovered that maintenance would be active only during the time in which the main period overlaps with sub periods. But what's the point of defining the same thing twice? Couldn't the one-time period be the only thing to specify? The benefit of the main period becomes more apparent when configuring recurring maintenance, so let's explore the options available for sub-periods. Navigate to Configuration | Maintenance, start creating a new maintenance, and play with the available sub periods as we explore them.