For most homes in Brooklyn, Queens, and Nassau County, cleaning gutters twice a year works: once in late spring after the seeds and blossoms come down, and once in late fall after the leaves. That keeps the system clear for summer storms and for winter, when clogged gutters freeze and create ice dams.
Homes under big trees, especially oaks and maples, often need a third cleaning. So do houses with complicated rooflines, where valleys funnel a lot of debris into one short run of gutter.
Watch for the signs between cleanings: water spilling over the front edge during rain, gutters pulling away from the house, plants growing in them, or puddles and erosion near the foundation. Any of those means water isn't going where it should.
A good cleaning isn't just scooping leaves. We flush every downspout, check that hangers are tight and seams aren't leaking, and look at the fascia behind the gutter for soft wood. Catching a loose gutter or a rotting board early is far cheaper than repairing a wet basement.