Clifton's median house dates to 1951 and Hawthorne's to 1953. Little Falls is at 1957 and Totowa at 1958. A roof on a house from those years is rarely the first one. Sometimes the last crew stripped it, and sometimes they nailed new shingles right over the old ones.
Under the shingles on a house that age, there can be the original wood boards instead of plywood. A board can look fine from the attic and still be soft where the nails go in. With the roof open we walk each one, and any board that has to go shows up in a photo, with its cost, before we cut it out.
The north end of the county is younger and colder. West Milford, Ringwood, Wanaque, Bloomingdale and Pompton Lakes are in the Highlands, where snow sits on a roof longer and ice can build at the eaves. Down in Clifton and Paterson, the age of the house is the bigger question.
A street view of a 1950s Clifton roof tells you nothing about the layers. We go up, look in the attic, and count them before any number goes on paper.