After two years, the Roomba started breaking down. First, the Roomba would not charge even when seated in its dock. The orange light would not pulse. The other behavior was that it would approach the dock, when the dock button was depressed, but it would twist, turn and collide with the dock as if it could not detect it. I finally called tech support, and we went through all the typical steps: resetting the Roomba, making sure the contacts touched the dock, etc. The odd trick that got the Roomba working again was to spray compressed air into the battery charging outlet.
So, the Roomba was charging again, but it would not return to its base. It would run out of juice before the cleaning cycle ended, which tells me that cleaning cycles are timed, instead of based on the remaining charge in the battery. After a few more weeks of delay, I finally ordered a new battery.
Installing the new battery was easy. Just remove a few screws. I also cleaned the Roomba at the time. With the bottom panel removed, I could see dust everywhere. So, the Roomba has been working like new again. On one hand, I’m disappointed that the battery only lasted two years. However, it was working every single day during that stretch, which is more work than all the other vacuum cleaners I have owned have put in to date.