How long do cedar wood fence posts typically last?

Untreated cedar wood fence posts typically last 15 to 20 years, and treated cedar posts normally last 20 to 25 years, according to the Virginia Cooperative Extension website. Pressure treating fence posts consists of forcing chemicals down into the wood, and this preservative solution helps protect wood from rotting.

Untreated cedar fence posts also have a long lifespan due to the natural repellent properties of the wood. The heartwood of cedar trees, which is the dark red center that extends outward, contains natural oils that destroy fungal diseases, and the aromatic scent of cedar repels insects, such as termites, that destroy wood.