I built the Deck at my Mom's house when I was 19 years old. 12x16 with 2"x2" spindle handrail and 2 sets of steps 27 years ago. I have never replaced one single board on it and it is just as structurally sound today as it was 27 years ago. People think "Lifetime Warranty" on the treated lumber they buy is against everything. That is usually only against rot or termites. Water damage will destroy a Deck or Fence just as quick if left untreated. Like potholes in the winter the most damage is done in the winter. Water soaks into the wood and then freezes and expands causing cracks. These get bigger and bigger as more water freezes. Whether it is a wood structure, concrete patio, driveway or sidewalk, power wash and seal to get the max life out of it.