Question about iRobot Roomba j9+

The dust bag for the Roomba j9+ is not needed every time it is emptied, as the robot is equipped with an automatic suction station, the Clean Base. This station empties the dirt for up to 60 cleaning days and refills the liquid for up to 30 cleaning days. The collection container is therefore emptied automatically when the robot returns to the Clean Base. A new bag is only required when the existing one is full or after a certain number of cleanings, which is minimised by the automatic station.