The short answer is: a good wooden park bench can absolutely last as long as a metal one, and in some conditions it will outlast a cheap metal bench. But the real question is not just wood versus metal. It is what kind of wood, what kind of metal, how the bench is built, and how much maintenance you are willing to do.
A cheap pine or untreated fir bench is mostly about the look. It will absorb moisture, warp, crack, and start rotting in three to eight years, especially if it sits in wet grass or shade. That is the kind of wooden park bench that gives wood a bad reputation. But a bench made from teak, ipe, white oak, robinia, or thermally modified ash is a completely different product. These hardwoods are dense, naturally rot-resistant, and stable outdoors. A well-built teak or ipe bench can easily last 25 to 40 years with basic cleaning. I have seen old teak benches in parks that are still solid after three decades while the steel benches next to them have rusted at the joints.
Metal benches are not automatically permanent either. Cast iron is extremely strong, but it is heavy, brittle, and the paint eventually chips. Once moisture reaches the iron, rust starts spreading around bolt holes, feet, and seams. Tubular aluminum will not rust, which makes it great for coastal areas, but cheaper aluminum frames can bend, fasteners loosen, and the powder coating fades over time. Painted or powder-coated steel sits somewhere in between: strong and affordable, but as soon as the coating gets scratched, rust can travel under the paint. A steel bench in a dry climate may last 20 to 30 years, while the same bench in a coastal or wet environment may need serious attention within a decade.
So are you just paying for the look? Only if you buy a low-density wood bench without rot resistance. If you choose a quality hardwood park bench, you are paying for longevity, stability, and a surface that stays cooler in summer and warmer in winter than metal. Metal benches are not a one-time purchase either. They need repainting, rust treatment, and replacement hardware over time. That cost is often hidden because it happens later.
Maintenance is the other half of the lifespan equation. A hardwood bench needs occasional cleaning and, depending on the finish, a yearly or biennial oil or sealer if you want to keep the original color. If you let teak or ipe go gray, it still lasts, just with a weathered look. Metal needs inspection for scratches, touch-up paint, and rust removal around joints. Stainless steel hardware matters on both types. A beautiful teak bench assembled with cheap steel bolts will stain and fail at the fasteners long before the wood does.
If you want the longest life with the least hassle, look for a bench made from ipe, teak, or white oak with mortise-and-tenon joinery and stainless steel hardware. For metal, choose thick-gauge aluminum or properly powder-coated steel and check that the coating is thick and evenly applied. Avoid thin tubular metal and low-density softwood if lifespan is your main concern.
Ultimately, a wooden park bench is not automatically a worse investment than a metal one. The material grade and build quality decide durability far more than the simple wood-versus-metal label. Buy high-density hardwood and maintain it lightly, and it will likely sit in your park, garden, or backyard as long as any metal bench you could buy. Buy cheap softwood, and yes, you are mostly paying for the look.