Over time your dryer vent becomes coated with dryer lint. If left uncleaned your duct can become a real fire hazard. It’s not enough to clean your lint screen every time. If your dryer vent is over ten feet long yealy dryer vent cleaning is recommended. Lint is not the only thing that can block a dryer vent. If you run your dryer and forget to put the lint screen in A piece of clothing could easily get sucked into your vent and get lodged at the exit. This is something we see often.