There is no single dryer-vent cleaning interval for every home because vent length, number of bends, duct type, and laundry volume change how quickly lint builds up. A practical baseline is to inspect at least annually and clean sooner when restriction signs appear.
Use one year as a review point, not a guarantee
A short straight vent may stay cleaner longer than a long run with several bends. Inspect the route and adjust frequency based on what you actually find in your installation.
Clean sooner when drying time increases
Longer cycles, an unusually hot dryer, or weak airflow at the exterior termination can indicate restriction. Before blaming the appliance, check the lint screen and vent because buildup increases temperature and fire risk.
Long or shared vent runs need closer attention
Runs with many bends, roof terminations, or multifamily configurations can be difficult to clean and inspect. If the full route cannot be reached safely, use a professional service that can verify the complete vent path.
Clean the lint screen every load
Annual vent maintenance does not replace cleaning the lint screen after every load. Keep the exterior termination clear as well, and stop using the dryer if there is a burning smell or other sign of overheating.