The frequency of cleaning ducts depends on various factors, such as the amount of dust and dirt present in the home, the presence of pets, or the frequency of using the HVAC system. However, in general, it is recommended to clean ducts every 3 to 5 years.

Cleaning air ducts is necessary to ensure proper airflow and prevent the accumulation of dirt, dust, and other pollutants that can affect indoor air quality. It can also help improve the efficiency of your HVAC system, reduce energy costs, and prolong its lifespan.

Cleaning dryer vents is important to prevent the buildup of lint and debris that can obstruct the airflow, cause overheating, and increase the risk of fire. It can also help improve the performance of the dryer and reduce energy costs.

The frequency of changing air filters depends on several factors, such as the type of filter, the level of indoor air pollution, and the usage of the HVAC system. However, it is recommended to change air filters every 1 to 3 months.

Some potential hazards of not maintaining a clean and functional home ventilation system include poor indoor air quality, increased risk of allergies and respiratory problems, decreased efficiency and lifespan of HVAC systems, higher energy bills, and increased risk of fire hazards (in the case of unclean dryer vents).