The answer to 'how to maintain ductwork' is to regularly inspect, clean, and seal your ductwork to improve efficiency and indoor air quality. This involves visually inspecting ducts for damage, leaks, or debris, cleaning accessible ducts, and sealing any cracks or gaps with duct sealant or metal tape.
It's recommended to have your ductwork professionally inspected and cleaned every 3-5 years, or more frequently if you have pets, smoke indoors, or notice a decrease in HVAC efficiency. Homeowners can also perform basic maintenance tasks like replacing air filters and removing dust buildup from vents on a regular basis.