How often do need to replace Asphalt Shingle Ontario Canada?

a roof that was shingled correctly usually lasts around 10 years (in Michigan). You will be able to tell from the shingles and the look of the roof how recently the roof was redone. look for discoleration, shingles loosed or pulled up from the roof, etc. discoleration in the central areas of the roof are a bad sign, unless the roof is 10+ years old. damage usually starts around the chimney, plumbing vents and the eaves.