We clear them by hand, flush the downspouts, and test that water actually leaves the property. That last step is the one that gets skipped.
Most of the country cleans gutters once, in late fall, after the leaves come down. Omaha has a second season that arrives four months earlier and catches people out.
From late May the cottonwood drops its seed fluff. It is light, it travels, and it collects in gutters in volume, and unlike leaves it does not sit loose. Wet cottonwood mats into a dense, felted layer across the bottom of the gutter and over the downspout opening. Silver maple samaras come down around the same time, and their stems knit into that mat and lock it together. By the time the July storms arrive you have a fibrous plug sitting exactly where the water needs to leave.
Then the actual leaf drop comes in October and November and lands on top of it. A gutter cleaned only in November spent the entire storm season, the months with the heaviest rainfall Omaha gets, already blocked.
That is why the two-visit schedule here is genuinely different advice rather than an upsell: early summer after the cottonwood finishes, and late fall after the leaves are down.