Does air duct cleaning actually help?
An honest answer, including when it doesn't.
When it's worth it — and when it isn't
Duct cleaning genuinely helps in specific cases: visible mold, vermin, a recent renovation, or heavy documented buildup. Studies have not shown that routine duct cleaning, absent one of those reasons, meaningfully improves the air in an average home.
So the honest guidance is: clean your dryer vent on a schedule, and clean your air ducts when there's an actual reason — not just because a coupon arrived.