You’ll need to restrain your deck when you notice fading, cracking, peeling, or mold and mildew over a moderate to large area, or when it’s become especially difficult to clean. As for how often to stain a deck, plan to do it every two to three years or whenever you start to notice extended damage.

To make sure the paint won’t bubble as you apply it, make sure to paint on a day that’s cooler than 85 degrees Fahrenheit. When the temperature is too high, the paint won’t dry evenly, which can result in bubbles forming on the surface. Another way to prevent paint from bubbling is to clean the walls, apply primer, and let everything dry completely before you begin.

Whether to brush or roll stain on wood depends on the project and your preference. Brushing is ideal for smaller, intricate areas and offers more control over the application, ensuring thorough coverage and penetration into the wood's grain. 

Conversely, rolling is efficient for more extensive, flat surfaces and can save time. However, it is not always the best fit for textured or uneven wood. Some projects may benefit from combining both methods, using a brush for detail work and a roller for broader areas. Ultimately, the choice between brushing and rolling depends on the specific requirements of your staining project.

Applying a sealer or topcoat after staining wood is highly recommended, though not always strictly required. A sealer protects the wood from moisture, UV rays, and weather-related issues, which is especially important for outdoor surfaces like decks and fences. It also enhances the stain's durability, prevents fading over time, and gives the wood a cleaner, more professional-looking finish. For some indoor applications, a sealer may not be necessary, depending on the type of stain used and the level of protection needed. It's always best to check the stain manufacturer's recommendations and consider the wood's intended use and exposure when deciding whether to apply a sealer.