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.

Adding a second coat of stain to wood can even out the color to some extent, but it won't drastically alter the hue if the initial application is too light or too dark. It's more effective at enhancing the richness of the color rather than significantly changing it. Ensure the first coat is dry before applying the second.

Whether you can paint over your existing paint depends on what’s on there. Most of the time, you’ll want to sand down or scrape off the paint that’s currently coating your surface. Epoxy paint, for example, won’t let new paint stick to the surface. Latex paint is more forgiving and will accept a new coat, but a primer is recommended if you’re switching colors.

Staining or sealing a cedar deck or fence is highly recommended to extend its lifespan and protect it from the elements. While cedar is naturally resistant to mold and mildew, it is not impervious to damage from moisture, sun exposure, splintering, fading, and rot over time. Applying a protective finish creates a shield that preserves the wood's strength and appearance, potentially extending its life by five to 10 years.

When choosing a finish, it's helpful to understand the difference between a sealer and a stain. A sealer sits on top of the wood, whereas a combination stain and sealer soaks into the top layer. Because it penetrates the wood, a stain generally offers better protection against UV damage and rot and lasts significantly longer. For the best results that also preserve the wood's natural color, consider using a near-translucent stain.

To maintain protection, plan on reapplying the stain or sealer every two to three years, either as a DIY project or by hiring a professional.