The dryer vent is a fire-safety job dressed up as a cleaning job

Your lint trap catches some of it. The rest goes into the duct behind the dryer and accumulates, particularly at bends and at the exterior flap. As the passage narrows, hot moist air can't escape, so the dryer runs longer, gets hotter, and the thermal cutoff starts cycling. That's the failure mode that ends in a fire.

The signs you already have

• Clothes take two cycles to dry — the single most common symptom.
• The dryer or the laundry room is hot to the touch after a load.
• A burning smell, even faintly.
• The exterior flap doesn't open properly, or you can't feel strong air coming out.
• It's been more than a year, and nobody has ever done it.

Condos and long duct runs

This is a specifically South Florida problem. In a high-rise, the run from a stacked laundry closet to the exterior can be twenty feet or more with several bends, sometimes shared through a building riser. Those clog far faster than a house's four-foot run, and residents almost never think about them because the vent isn't visible from anywhere in the unit. If you're in a tower and have never had it done, it needs doing.

What we do

Rotary brush through the full length of the duct with a vacuum on the other end, then we check the exterior flap actually opens and closes freely — a stuck flap undoes everything else. We'll also flag a duct that's the wrong material: flexible foil or, worse, vinyl accordion hose is a code violation in most cases and needs replacing with rigid metal.