Most Tualatin Valley homes need it twice a year, once after the autumn maple drop and once in spring to clear the fir needles that accumulate through winter. Homes with a heavy Douglas fir canopy often need more, because fir sheds year round rather than in one season. We tell you which schedule your roofline actually calls for.

Late fall, once the big-leaf maples have finished dropping, is the most important clearing of the year, because it sets up the gutters for the heaviest rain. A spring visit then clears what built up over winter. Fir needles keep falling in between, so a mid-canopy home benefits from a look between those two.

Water backs up over the edge and runs down the fascia and siding instead of leaving through the downspout. In this climate that wet wood rots and grows moss quickly, and overflow pools against the foundation. Clogged gutters also hold weight, which pulls the run loose from the fascia over time. Clearing them is far cheaper than the repairs that follow.

The most useful clearing is late fall, before the heavy runoff starts, so winter cleaning is usually about catching what fell after that. Douglas fir keeps shedding through the cold months, and a mat of wet needles blocks a gutter as completely as leaves do. If your home sits under evergreens, a winter check is worth it even after a fall cleaning.

Look for water spilling over the edge in rain, plants or seedlings sprouting from the trough, and streaks of dirt down the siding below the gutter line. Sagging sections and downspouts that stay dry during a downpour are also signs. Under a fir canopy the trough can be full while still looking clean from the ground, so a seasonal check matters.