Archaeological sites still yield tiles dating back several millennia... Unless there is a manufacturing defect, which is unlikely today thanks to technological advances and controls at the factory gate, the tiles are guaranteed to withstand the elements for several generations, but still not to withstand hammer blows! The quality of the clays used, a noble material, and the respect of the manufacturing standards, are the key to the quality of a good tile. The lifespan of a clay tile can be around 100 years or more, especially if the roof is well maintained and well ventilated.