-Missing tabs or shingles. Individual shingles can be blown or knocked off in high winds or stormy weather. This may be easy to repair, but if there are multiple shingles missing, it may be a sign your roof needs to be replaced.
	Cracked or worn out caulking, roof cement, metal and flashing. Areas around skylights, vents, pipes and valleys are typically the most stressed areas of a roof. These are the most likely places a leak will occur.
	Worn or weathered shingles. Thin shingles, shingles with curled edges, up or down, cracked shingles and shingles with the top layer of granules washed off, all indicate that your roof may need to be re-done.
	Exposed nails may also cause roof leaks.