My robot from the Roomba 900 series has been living in a house with three people and an outgoing dog (shorthair) for over 4 years. After 4 years the side brush broke completely, the scuff marks on both rollers looked worn and it just ran but didn't vacuum. I cleaned it thoroughly and it still didn't work; I was ready to buy a new one! After spending 5 minutes installing new rollers, filters and side brushes (with just a flat head screwdriver) my Roomba is working great again! I wasn't 100% expecting this to work, figured I'd have to buy a new vacuum or send it back for service - I'm SO HAPPY with this kit!