Are you having to run the dry cycle again and again?
You need your dryer vent cleaned out. As your clothes dry, steam forms and is pushed out by the dryer (seen on a cold day where the dryer vents outside). The steam creates moisture on the inside of dryer duct and the lint that passes your dryer screen is blown down the duct and adheres. Over time it closes off the air flow.
This is a fire hazard.
Getting your dryer vent cleaned will save you time and money... and may even save your house!