Rot at the eaves
The edge of the roof works harder than any other part of it. Every drop the field sheds crosses the eave on its way out; whatever the gutters cannot carry comes back over it; and in this climate the eave is the last part of the roof to dry after each of a hundred and fifty rains a year.
How an edge dies
The sequence repeats across the region’s housing. A packed gutter overflows and wets the fascia; the fascia stains, then softens. Moss on the lower courses holds water at the shingle edges until they lose their granules and their stiffness. Water finds the gap between drip edge and gutter — or the place where there is no drip edge at all, common on older work — and starts wetting the first inches of deck. By the time anything is visible from the ground, the bottom courses and the deck edge have been wet on and off for seasons.
This is why so many Sound-area roofs read two ways at once: a field with years left, and edges that are finished. An honest evaluation prices that reality — how many feet of eave, how much starter course, how much deck edge — instead of averaging it into a verdict about “the roof.”
What keeps edges alive
Gutters that actually drain, cleared on a conifer schedule rather than a deciduous one. Moss controlled before it reaches the bottom courses. Drip edge on every re-roof — cheap insurance that much of the older stock never got. And at replacement, a contractor who quotes the eave work explicitly: on this housing, the edges are where the surprises live, and a per-foot price for fascia and deck-edge repair keeps the surprise from becoming a change order.