I feel like I use my Roomba 6+ a lot which I bought 3 months ago. With kids and dogs, I've run this thing - I put these interchangeable parts in to test it out, although I haven't had to change it yet. All items seemed to work. Strangely, one of the videos seemed to be a bit longer, but that didn't seem to matter as it came in with no issues. The car seemed a little noisier than some were reporting but I actually think it was because they were fresh full traction rolls. Guess that's what it sounded like when I first got it. In any case, I received these parts in a couple of weeks and have done dozens of jobs. I'd buy again, but I actually think the stock I bought will keep me in good shape for some time to come.