Staining a deck with a rag is typically a better option than using a brush, as it helps the stain penetrate deeper into the wood. However, both brushes and rags are best reserved for detailed work because using these tools on an entire deck can require tediously crawling around on your hands and knees. A pad applicator, sprayer, or roller are preferred alternatives to applying stain over the majority of a deck. Use a rag for railings and other detailed work, and let the wood soak up as much of the stain as possible before wiping away drips or pools.

Deciding whether to stain or paint a pool deck depends on your budget, desired look, and the deck's material. Both options can work. Paint offers a wider variety of color options, provides excellent water resistance, and can last longer. However, it requires a primer and can eventually fade or peel. Stain is often cheaper, easier to apply, and penetrates the wood for a more natural look and longer-lasting finish. It also has great water resistance. The downsides are fewer color options and the need for a sealant. The choice can also depend on the deck material; for example, staining may be a better option for concrete as it bonds well and lasts longer than paint.

If you want to achieve a deeper, darker stain color, wait 5 to 10 minutes before wiping it off. However, wipe it off faster for a lighter tone. When wiping off the stain during this part of the process, be sure to work in the direction of the wood’s grain for best results.

In most cases, sanding an old deck before staining it is necessary to achieve a decent finish. If your old deck has a relatively new stain finish on it and you're only doing touch-ups, you can generally skip the sanding part. However, if your goal is to make the deck look and function better, sanding first is a must.