In a coastal city with salt air, a good-quality outdoor bench typically lasts 10 to 20 years before it needs major refinishing or replacement. But the real answer depends heavily on materials and exposure. A cheap pine or basic steel bench may only give you 3 to 7 years, while marine-grade stainless steel, high-density recycled plastic, or concrete can last 20 to 30 years or more.
Salt air works constantly. It accelerates rust on ferrous metals, dries out and fades wood, corrodes protective coatings, and even pits lower-grade stainless steel. That means a bench in a coastal town will rarely last as long as the same model would inland. I usually tell people to plan for roughly half the manufacturer’s advertised lifespan unless the bench is explicitly built for marine environments.
If you want the bench to last, choose materials made for seaside conditions: marine-grade stainless steel, powder-coated aluminum, teak, shorea, or high-quality recycled plastic. Rinse the bench with fresh water regularly, especially during dry, windy months when salt spray accumulates without rain. Keep metal hardware coated or sealed, and reapply protective oil or sealant to wood every 6 to 12 months. Small steps like tightening fasteners and touching up scratches before rust takes hold can add years.
So for a realistic range: basic wood or steel might give you 3 to 7 years; coated aluminum or teak can give you 10 to 20 years; marine-grade stainless steel, recycled plastic, or concrete can last 20 to 30 years or longer with basic care. In a harsh, exposed seafront spot, assume the lower end. In a more sheltered seaside garden, expect the higher end.