Decks are functional and can be a compliment to the backyard atmosphere or an eyesore. Rotten or discolored deck boards can put a damper on BBQ's.
A deck worth keeping should be inspected and maintained at least once a year. Cleaning with a pressure sprayer is ok if the deck is built of CCA treated dense pine. In the case of Cedar or Redwood, a pressure sprayer is not advisable. There are clear deck finishes that protect against UV rays and moisture damage. There are also other coating products for decks that are colored to suit the decor of the home, red, blue, green and many other shades.
Though the product label may recommend re-coating every couple of years, it's really better to inspect, repair and coat annually for best results.