First, ask what it takes to maintain the deck stain. How many coats of stain does the stain manufacturer recommend to optimize the stain’s performance? Also, is the stain rated for protection lasting one year? Two years? Three years?
As a general rule of thumb, stains lasting up to three years may be a bit pricier—but the cost is outweighed by the fact that you don’t need to do anything additional to maintain it until year two or three.
Next, ask how it performs. The farther down a stain penetrates deeply into the wood grain, the better a chance you have of enjoying its effects for a long time coming. Also, consider how well rated a particular stain is for resisting the sun’s harmful rays. What type of UV protection does it offer? That’s a good question to start off with.
Finally, ask how durable the deck stain is. A good stain can protect your precious woods for two to three years. A good question to ask is whether the exterior wood stain contains a fungicidal preservative—this can go a long way toward protecting your decking from decay and wood rot. Also, some stains contain transoxide pigments and mildewcide, which also can help protect your deck.