Aside from having parts available, I was unexpectedly impressed that my RoboRock self-emptying dock (c. 2023) was clearly designed for painless serviceability. The ducts are easily accessed via removable panels, and you need only a Phillips screwdriver.

That said, the performance of the robot certainly degraded over time, and I haven't identified the cause to my satisfaction. Obstacle avoidance needs work (especially for charging cables left dangling off the couch), and the map is frustrating to edit and seems to degenerate over a 6 month period.