The dryer takes hour to dry a small load

The most common cause of long dry times is too much lint; the dryer can't circulate air properly. Check the exhaust outlet and hose, from the dryer all the way to the outside of the house. Sometimes you'll even discover bird and squirrel nests blocking the air way.

If all is clear, check the operating temperatures. You can do this quickly by inserting a small food thermometer into the exhaust hose (If you're using the flex hose).