Rutherford's median house dates to 1945, and Teaneck's and Ridgewood's to 1950. A roof on one of those houses has usually been replaced before, and sometimes the last crew nailed new shingles over the old ones instead of stripping them. Under the shingles there may be the original board decking, not plywood.
Board decking changes the job. On some older houses the planks were laid with gaps between them, and a board can look fine from the attic and still be soft where the nails go in. We walk every board with the roof open. If one needs replacing, you see the photo and the price first.
Mahwah is the exception on age. Its median house dates to 1984. Up there, and in Oakland, snow is the bigger concern. Both towns are in the Highlands, where the State Climatologist puts average snowfall at 40 to 50 inches a year. Most of the rest of the county sits near the line where winter storms switch between rain and snow, so slush settles in gutters and roof valleys and freezes again overnight.
So we do not price a Bergen County roof from the street. We get on it when it is safe to, check the attic, and count the layers first.