How often should I clean my dryer vent?

This is the maintenance task with the worst ratio of importance to attention. Dryer vents cause thousands of house fires a year, the mechanism is entirely preventable, and almost nobody has it on a schedule.

Why it is a fire issue

The lint trap catches most lint, not all of it. What escapes accumulates in the duct between the dryer and the outside wall. Lint is dry, fine, and highly flammable, and a restricted duct means the dryer cannot exhaust its heat — so the machine runs hotter, right next to an accumulating pile of tinder. That is the whole failure mode.

What changes the interval

• Duct length and bends: a short straight run to an exterior wall stays clear far longer than a long run with several elbows.
• Duct material: flexible foil or vinyl accordion duct traps lint in every ridge. Rigid or semi-rigid metal is both safer and stays cleaner.
• Volume: a household doing several loads a day should think semi-annually rather than annually.
• Pets: pet hair loads a vent much faster than clothing lint alone.

Signs it is overdue right now

• Clothes taking two cycles to dry — the single most common symptom.
• The dryer or the laundry room noticeably hot after a cycle.
• A musty smell on supposedly clean laundry.
• Little or no air movement at the exterior vent hood while the dryer runs.

DIY or pro

A short, accessible duct is a reasonable DIY job with a vent brush kit: unplug the dryer, disconnect the duct, brush it through from both ends, and check that the exterior flapper opens freely. A long run, a second-floor laundry, or a roof termination is worth paying for — typically $100–200, and the tech will have a rotary brush that reaches where a hand kit will not.

While you are back there, clean the lint trap housing itself, not just the screen. A surprising amount collects in the slot below it.