Must have
You bought the Robo vac for convenience so buy the station. Our Robo cleans a 4X2 house every day and the dock takes 3.5 to 4 weeks to fill.
NOTE: When you first set up and run the vac and the station, the vac will be so full it will be unable to empty 100% of its load to the station, but after 3 complete house cleans it now empty every time. How often do you clean under beds? Yeah never, it amazing how much fluff the vac pull up.
Also note that in the instructions you need the station on a wall with 0.5 meters clear on each side, we have met this requirement and the vac has only ever lost the station once in 6 months.
A simple question in the end, Do you want to empty once a month or once a day?