The condition and lifespan of your roof depends on the type of roof you have, the effects of your local environment and the maintenance the roof has received. According to the American Society of Home Inspectors, asphalt shingles generally last 15-50 years; wood shingle/shakes, 10-40 years; clay/concrete tiles, 20+ years; slate, 30-100 years; metal roofing, 15-40+ years. Roofing product manufacturers offer a variety of warranties on their products. Take a close look at those warranties to see what responsibilities and financial obligations they will assume if their products fail to reach their expected lifetimes.