Wood stains last anywhere from two to five years, depending on exposure to the elements, your local climate, the type of stain, and the surface it’s on. For instance, vertical surfaces last longer than horizontal surfaces. Some types of woods, like dense hardwoods, will require a recoat yearly, as they are too dense for the stain to absorb. In any event, apply a recoat every 2 to 4 years. As for storage, a can of unopened stain can last up to 5 years, though results may vary.

You’ll need to wait until the surface is completely dry, which can take anywhere from 24 to 48 hours under optimal conditions. The waiting period depends on several factors, including the type of siding and the weather conditions. Trying to paint before the surface is completely dry can trap moisture under the paint, leading to bubbling, blistering, and mold growth.

Many decking oils can help slow down algae growth, but they don't completely stop it. These oils work by sealing the wood, which reduces moisture and, therefore, algae growth. Some decking oils also help protect against UV damage, but they need to be reapplied according to the manufacturer’s instructions to ensure the decking stays protected.

Painted decks typically require a new coat about once every ten years. In between new coats, it's best to maintain your deck by regularly removing debris, washing it down with non-abrasive cleaners, and staying ahead of structural issues, such as loose boards and rotting wood. In some cases, painting a small section of your deck affected by damage or the sun can lower your costs and workload.