A roof lifespan should match the length of the warranty period from the shingle manufacturer. For example, a 3-Tab shingle with a 25-year warranty should last 25 years if installed properly. However, improper installation or ventilation may cause your roof to wear prematurely and need to be replaced sooner. Therefore, we recommend having a thorough evaluation by a roofing professional when your roof is about 80%-85% (20 years into a 25-year shingle) through its lifespan to check for things like curling shingles, frayed edges with fiberglass matting exposed, and thermal cracking to better determine if your roof needs replacement or is in good health to keep you dry for the remaining period.