Describe an observation, not a diagnosis
Record where and when you noticed moisture, odor or debris and whether it follows recent work or a change in system operation. A location or symptom alone does not identify the cause.
Ask the right inspection questions
Ask the existing HVAC maintenance provider or an appropriate assessor to explain the condition and what they can verify. EPA notes that mold-like material may require expert identification. Do not assume that the entire system needs cleaning based on a surface observation.
Correct the source
If a moisture or contamination issue is identified, ask what caused it and what correction is proposed. A cleaning package alone may not address that cause.
Look at the wider indoor-air picture
EPA discusses source control, ventilation and filtration in its homeowner guidance. Duct cleaning is not a guarantee of better health, and filters do not remove every pollutant. Use the linked guidance to frame a conversation about your home.
Compare specific work
Ask for a written assessment, included work and exclusions. Keep dryer exhaust cleaning and any proposed HVAC add-ons as separate decisions rather than accepting a bundle without an explanation.