Over time, lint, dust, and other particles that make their way through the dryer system can accumulate in your dryer’s duct work inhibiting airflow, causing a drop in dryer performance, a rise in your energy costs, and, most importantly, a dangerous fire hazard.

 If you notice any changes in how well or fast your dryer is working–or if you simply know that you haven’t cleaned your dryer vent in a long time–it’s worth your while to bring in a professional to perform a thorough cleaning.   (http://EzineArticles.com/6276677)