When you buy something that will do all your dirty work like a Roomba, I think it goes without saying that some maintenance might be needed in the future. It's like an electronic relationship. You care about him, he cares about you, or at least your gender. My Roomba 770 is over a year old and just stops filling the litter box. Disassembled, cleaned, changed brushes, but nothing helped. I finally bought a replacement cleaning deck and viola, IT'S LIKE NEW! It's quiet here and I really realized how dirty a house can get in his absence. The replacement took less than 2 minutes and is a complete replacement of the brushes and all. Great buy for amazing results.