Storms may cause the roof to be replaced before the normal life of the roof is reached. High winds can blow shingles completely off the roof or hail storms can damage the toughest of shingles. Hail loosens the granules on the shingles creating dark spots on these shingles. The result is a shortened life span of the shingle. The loss of granules will allow the moisture to penetrate the core of the shingle accelerating the decomposition of the shingle.
Animal damage, though limited to a specific area, is an indication that the roofing material or wood substructure has deteriorated to the point that animals can more easily remove the shingles, siding, or roof deck to get to the attic for shelter. This may require only a repair, but it is a good time to inspect the remainder of the roof to determine the overall condition of the roof.