Many new homes in the Pacific Northwet, older homes too, have gutters installed that have open ends. These are almost always on dormers so they drain the water from that smaller roof down to the end of the gutter where it keeps on a movin' down the rooof to the main gutter system. Many builders, and buyers, feel that the look of open-ended gutters far exceeds the look of a long downspout going down the roof. That may be true to some people, but open-ended gutters have their own issues. One of those issues is they dump heavy water, especially during major rain, near the siding at dormers (hope the metal flashing at the wall is good) and that river of water does, over time, deteriorate the granular material on compositon shingles. After only a few years, you can see the track of the water. When that granular material goes, UV from the sun will take a toll on the roofing as well. This arrangement stresses wood roofing too.
These open-ended gutters, due to design and neglect, often have blocked ends. Organic debris loves those ends, see the photo below. You will notice that there is exposed wood at the end of the gutter. That is very common and should be avoided. The gutter will be running water against this in the best of times. In the worst of times, a big soggy sponge of debris will be resting against the wood. That causes rot.
Steven L. Smith
Bellingham WA Home Inspections
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hhmm, I can see how that would be a problem and wear down the room shingles.
Sean Allen