I don’t know what took me so long to replace my side brush on my Roomba. It works noticeably more efficiently with a new brush. You will need a Phillips-head screwdriver. It was easy to unscrew, pull right out, and pop the new one in. Each brush even comes with its own screw. Roomba recommends the side brush be replaced every 6-12 months. I waited much too long to change mine.