There's no single timeline for repainting or restaining a wooden bench, as it depends heavily on several factors. Generally, you should inspect your bench annually and plan for a full refresh every 2 to 5 years.
The primary factor is exposure. A bench in full sun, rain, and snow will need attention more often—perhaps every 2-3 years—than one under a covered patio. The type of finish also matters. A penetrating oil-based stain may fade and need reapplication every 2-3 years, while a solid-color stain or paint film can last 4-5 years before chipping or peeling requires a full repaint.
The wood itself is crucial. Dense, rot-resistant woods like cedar or redwood can often go longer between treatments compared to pine. Always look for the telltale signs it's time: the wood looks gray and dry, water no longer beads on the surface, or the existing finish is cracked, peeling, or flaking off.
Proper preparation is key to longevity. Before any new coat, always clean the bench thoroughly, sand away loose finish, and let it dry completely. Applying a fresh coat of stain or a primer-and-paint system when these signs appear will protect the wood from moisture and UV damage, significantly extending the life of your beloved bench.