Ultimately, overapplication of stain can compromise the deck's appearance, durability, and longevity. It may result in an uneven finish, with excess stain pooling, dripping, or drying into thick patches. It can also obscure the wood's natural grain and texture, detracting from the desired aesthetic. Moreover, excessive staining may not fully penetrate the wood, leading to poor adhesion and premature wear. Additionally, thick layers of stain are prone to peeling, cracking, and blistering as they struggle to bond with the surface. 

Pressure-treated wood contains preservatives that give the material internal protection from rot and pests. Untreated lumber won’t last more than a few years unless you choose a more expensive wood, like cedar, that naturally stands up well to moisture. Composite decking can outlast wood but is more expensive and doesn’t look as natural. Keep in mind that you’ll need to seal any exterior wood product to protect it from the elements and other forms of external damage.

Cold temperatures can make your deck boards contract. If they don’t contract evenly, they can put pressure on the deck screws and cause them to pop out, making a noticeable sound. Winterizing your deck can help prevent this from happening.

The best way to sand a deck is by cleaning it, sanding the boards and stairs with 60- or 80-grit sandpaper, and sanding the railings and posts with 80-grit sandpaper. You should sand in the direction of the wood grain to avoid damaging the timber. When sanding your deck, use medium pressure and aim for an even sand. Pressing too hard with a sander can damage decks, as most are softwoods.