The age of the roof is sometimes determined by the amount of granules left on top of the shingle. The granules on top of the shingle are there to protect the waterproofing asphalt from UV rays. Once the shingle experiences major granule loss, the serviceable life of the roof is done. It’s very tough to tell the age of the roof. A properly installed roof using high quality materials can look great even at 20 years of age, while a relatively new roof at 9 years can look bad due to low quality materials.