It is essential to have your dryer's exhaust vents inspected and cleaned by a professional at least once a year. Commercial dryers are larger than residential models, so they don't need to be serviced as often. Generally, you should expect to have your dryer vents professionally cleaned every 3-5 years, depending on how frequently you use the machine. If you observe lint buildup, longer drying times, or a burning smell while your clothes are drying, it is time to call a professional.
The Consumer Product Safety Commission and the National Fire Protection Association both recommend regularly cleaning the dryer and ventilation system to prevent fires. Cleaning the dryer vent can also help improve its efficiency and reduce energy consumption. Experts suggest cleaning the lint filter after each load and the ventilation system at least once a year. If you find that you have to run the machine longer to dry your clothes, it is likely that the vents are clogged and need to be serviced.
You can also purchase an accessory that is compatible with most vacuum cleaner models and is designed to clean the dryer vent. Additionally, flexible plastic or aluminum vents should be replaced with metal dryer grilles that maintain a minimum diameter of 4 inches. Not cleaning the dryer's ventilation grilles can be hazardous, as lint accumulates and forces the machine to work harder.