Homeowners often ask whether their project really needs a permit. The short answer for the Portland metro: anything structural, anything that adds square footage, and anything that moves or adds plumbing, electrical, or mechanical systems does. Additions, ADUs, garage conversions, deck construction, and most kitchen and bathroom remodels with relocated fixtures all fall in that group.
Cosmetic work usually doesn't. Painting, replacing flooring, swapping cabinets in the same location, and replacing a vanity without moving the plumbing are typically permit-free. When in doubt, the city or county will tell you, and so will a contractor who does this every week.
Permits protect you. Inspections catch problems while the walls are open, permitted work is documented when you sell, and unpermitted additions can become an expensive problem at closing or with your insurer. The fee is small compared to the cost of redoing work.
When your contractor handles it, the process is mostly invisible to you: drawings submitted, review time built into the schedule, inspections scheduled at each stage, and a final sign-off at the end. Ask for it up front, and make sure the schedule in your estimate includes the review period rather than assuming it away.