The cheapest of asphalt shingles generally will be most susceptible to deterioration from temperature, wind, storms, and exposure to the sun, and may begin to show signs of damage within 5-6 years (possibly less) after their initial installation, and their overall lifespan is usually the shortest as well, averaging somewhere between 12 and 18 years. Shingle granules are typically applied to protect against weather, and sunlight and ultraviolet radiation. The process of aging speeds up as these granules wear away, and so leaks are more likely to occur as the shingles deteriorate.
Loss of granularity can result from numerous factors, ranging from expected wear and tear to foot traffic, blistering of the shingles, mechanical damage, hail, or even from defective product. Ice dams, poor ventilation, and growth of moss can also reduce the longevity of your shingles. In hotter and mostly sunny climates, lighter color shingles are best as they offer the most resistance to UV rays, heat, and drying out.
In hot and humid climates, however, shingles are more susceptible to fungal and algae, and you should consider special algae resistant shingles which are partially coated with leachable copper, protecting them against algae, moss, and general discoloration. Newly formulated algae resistant shingles are available from Atlas with a Lifetime Warranty, for example.
Most shingles suffer damage during hailstorms and will require replacement, but there are premium asphalt shingles from some manufacturers that are able to withstand Class IV hail storms. These are of similar durability to concrete tile or metal roofing.
