There are several signs that can inform you of the need to repair your roof. Go to your attic and look for beams of light coming through the top of the house. Also look for stains and streaks. These are indicators of a leaky roof.
Make sure your rooftop is in ship-shape, especially after heavy storms. Every shingle should lie flat against the roof. If there are any patches that are cracked, damaged, or buckling, roof repair is needed.
If the roof is younger than 15 or 20 years old and has been properly installed, it may get by with a repair rather than a full replacement. From experience we advise to always get a professional opinion.