Consumer Reports recommended two Behr deck stains from The Home Depot after testing more than 30 products to see which ones protect the wood the longest.
If you don't maintain your deck with a good stain, you'll probably pay for it.
"You'll spend more in the long run to replace the boards that havae gotten damaged," contractor Steve Bradsell said.
Consumer Reports tested deck stains on the roof of its headquarters, leaving stained panels out for years in all kinds of weather.
Solid stains look the most like paint. Others are semi-transparent, while clear sealers show the most wood grain.
"Clear sealers need the most maintenance. Even the best need to be reapplied every year," Consumer Reports' Bob Markovich said.
After more than a year a panels with clear sealers had lost color and began to crack.
When panels were left in the shade to see how well they resist dirt and mildew, the clear sealers performed the worse.
"Semi-transparent stains do better. They generally need to be redone every two years. Solid stains last longest. Most last at least three years," Markovich said.
One by Behr, The Solid Color Deck, Fence & Siding Wood Stain from the Home Depot, was the longest-lasting by far.
For people who prefer a semi-transparent stain, Consumer Reports recommended another one from Home Depot, Behr Premium Semi-Transparent Weatherproofing Wood Stain. It costs $36 a can.