The longevity of a standing seam metal roof largely depends on the type of metal used. Common materials include aluminum, galvanized steel, and zinc. Aluminum roofs are resistant to corrosion and can last 50 years or more, making them an excellent choice for coastal areas. Galvanized steel is coated with a layer of zinc to prevent rust, and when properly maintained, it can last 30 to 50 years. Zinc roofs can also last upwards of 50 years due to their self-healing properties and resistance to corrosion. The choice of material plays a crucial role in determining how long the roof will last.