If one gets a new asphalt? shingle roof with 20-year Monsanto? shingles, how long should it last? 20 years?
Mine is only 13 years old and has a small leak already. I can't see the back half of the roof from the ground, but the leak is in the middle, not by the chimney flashing.
I watched them put it on and they did a good job. They used famous name shingles, though I can't remember if it was Monsanto, 3M maybe.