We see a lot of decks, and one of the things I'm running into more and more are people who have been taken advantage of by the paint companies who sell products meant to salvage a tired deck. Among them are Rustoleum Deck Restore and Behr DeckOver. I just got off the phone with a man who has ruined a 5-year-old deck with DeckOver. Like most customers, he found that after spending hundreds of dollars to install this product, the product peeled up, leaving his deck worse than it was before. Please do some research before you spend significant time and money on a product that may do irreparable damage to your deck.
https://www.deckstainhelp.com/class-action-lawsuit-against-rust-oleum-deck-restore/
http://www.popularwoodworking.com/woodworking-blogs/deck-coatings-that-fail
https://www.youtube.com/watch?v=9cmkeR7BERg