While they are popular, they tend to degrade more quickly than other roofing material options. After a few years, weather conditions can wear them out, hail might damage them, and winds may rip them off.  If you collect run off your roof for use in a garden etc., granule loss from the asphalt may contaminate the water.  Shingles generally hug the contours of the roof deck, but may need some time to settle into place after install.  Architectural controls occasionally prohibit the use of shingles in a subdivision—always check to ensure you are familiar with your area before making your choice!