The longevity of your residential roof depends on a few factors:  1. If it was properly installed  2. If regular roof maintenance is performed  3. The type of roof you have:  - Flat roofs typically last upwards of 15-25 years  - Metal & steel roofs typically last more than 50 years  - Slate roofs should last 75-100 years   - Asphalt roofs typically last over 25 years  - Cedar shingles last anywhere from 30-50 years  - Copper metal roofs can last for up to a century