Lint buildup in the dryer exhaust vent is the leading cause of home clothes dryer fires in the United States, according to fire safety agencies that track home appliance fires. It’s also, by a wide margin, the most common reason for slow drying, overheating, and premature thermal fuse failures covered elsewhere on this site. Cleaning it is inexpensive, doesn’t require special skills, and meaningfully reduces both risks at once.
This is different from cleaning the lint filter, which should happen before every load. The exhaust vent is the full duct run from the back of the dryer to the outside wall or roof cap, and it needs attention on a schedule measured in months, not loads. If you’ve landed here from a dryer troubleshooting page, especially not heating or taking too long to dry, this is very likely part of the fix.
