All roofs, regardless of how durable they are, have an expiry date. By some point, they would start showing signs of wear and tear, water damage, and other roof problems. There are only so many times repairs would be helpful. You'd have to replace your roof at some point. The lifespan of the roof depends upon the materials used to build it. Composition shingles last about 12-20 years, while asphalt shingles last about 15-30 years. People usually replace their roofs after every 20-25 years. However, if you have been lax about the maintenance of your roof, then you could be forced to get a new roof way sooner than that. On the flip side, the more serious you are about the maintenance, the more you can delay new roof installation.