That's an excellent question! Caring for your wooden park bench is key to making it last for years. There's no single universal timeline, as it depends heavily on your local climate, the type of wood, and the bench's exposure. However, a good general rule is to inspect your bench annually and plan to re-stain or re-treat it every 2 to 3 years.
Think of the finish as the bench's protective skin. Sunlight (UV rays) breaks down the stain or sealant, while rain and snow cause the wood to swell and contract, leading to cracks. When the wood looks dry, faded, gray, or feels rough to the touch, it's crying out for attention. If water no longer beads up on the surface but soaks in instead, protection is gone.
For a precise schedule, conduct a simple water test each spring: sprinkle a few drops of water on the bench. If it beads up, you're likely okay for another season. If it soaks in darkening the wood, it's time for maintenance. In harsh, sunny, or very wet climates, you might need to treat it yearly. In more sheltered, temperate spots, you could stretch to 3 years.
Proper preparation is 80% of the job. Always clean the bench thoroughly and let it dry completely before applying any new product. Use a stain or sealant specifically formulated for exterior wood. By sticking to this proactive care routine, you'll preserve the wood's integrity and beauty, ensuring your bench remains a welcoming spot for relaxation for a long, long time.