Bare wood strips and planks (about $2 to $12 per square foot) are sanded, usually stained, and topped with three protective polyurethane coats after they've been installed. The process takes several days and isn't DIY-friendly for the average homeowner, so it's best to hire a pro. But some prefer the even look of bevel-less boards topped with a lower-gloss (though less durable) site-applied finish. You can also stain unfinished flooring almost any shade. And when it's time to refinish, site-finished floors save money. Removing or abrading a factory finish requires special products and takes more time and skill, so many contractors build an extra 30 percent into the cost.