UV Lights are what is used in Hospitals to eliminate any residual germs, bacteria, and infections.
Most homeowners, renters, realtors, and others have not cleaned their ducts since they lived in/owned the home
Air Purification Systems attract dirt, allergens, and Volatile Organic Compounds or VOC’s
The drain line can get clogged from any number of reasons but keeping the line clear will keep the unit running.
Cleaning the condenser will allow for better air flow making the unit last longer