Roofing problems make themselves known in the form of leaks and drips. Repair leaky roofs before ceilings and walls are damaged; better yet, check your roof at least once a year before the storm season (and after a major storm, if necessary). Most commonly shingle roofs fail at penetrations, pipes and venting coming through our roof.  If your roof is 5 years old or more, you  want to have a professional preform a maintenance inspection.