Performed air duct cleaning and sanitation on two 2 apartments. All vents and ductwork are clear of dust and debris at this time. Both units are functioning properly at this time. Recommend duct cleaning every 2-3 years. Performed dryer vent cleaning on 2 apartments. Dryer vents, flex hoses and lint traps are all clear of lint and debris at this time. Dryers are functioning properly at this time. Recommend dryer vent cleaning every 1-2 years.