It has been at least 18 years since our ducts have been cleaned. The before and after pictures of each duct was incredible evidence that we have neglected them; the photos validated that having the ducts cleaned is money well spent. I would love to have Felipe, the cleaning expert who worked at our house, be a guest speaker in my classroom to talk to my students about what he knows about punctuality, outstanding work ethic, professionalism, customer service, and craftsmanship. People in all professions could learn a lot from him!