How long a roof lasts will depend on the type of shingle, the brand of shingle, the quality of the shingle, and components of the roof, but it also depends on the skill of the roofers who install the structure.
On average, a roof will last for between twenty and twenty-five years. It’s rare to see one last much longer than that, but it does happen. However, poor workmanship during the installation could, in fact, reduce its life expectancy or cause premature failure of the roof system