Dryer Vent Regular Maintenance
Your dryer vent should be cleaned every 6 to 12 months depending on how much your dryer is used. Between cleanings:
Check your dryer vent every few months to ensure that it is not blocked or full of lint.
If your dryer is taking an unusually long time to dry, or if clothes are always damp, your dryer vent may be clogged
You can check your dryer vent by moving your dryer away from the wall and detaching the flexible duct form the back and looking into it.
If you have a short duct directly to the outside and a shop vac, you may be able to clean the duct out quite easily on your own.