We find most well-built roofs can last for approx. 20 years. It all depends on the materials used, for example, Slate tiles are known to last longer.
Of course, many factors dictate the length of time a roof maintains its integrity, such as the weather, which materials were used, how well they were installed initially and how well they have been maintained over the years. This is why you should always discuss the warranty of the manufacturers’ products.