The longevity of a coat of wood polish paint can depend on various factors, such as the quality of the paint, the type of wood being painted, the environmental conditions the wood is exposed to, and the amount of wear and tear the wood receives. Generally, a well-applied coat of wood polish paint can last several years, but it may require periodic touch-ups or reapplications to maintain its appearance and protection. It is also important to note that proper preparation and application of the paint can significantly impact its durability and longevity.