When I inspect decks in Bellingham and Whatcom County, not unlike at other areas of the country based on what I am told by other inspectors, I find a multitude of problems with decks. The average homeowner, hyped by being told how easy it is to build a deck on a weekend, often ends up constructing a monstrosity that is unsafe or will degrade the quality of the house. Some of the most common problems involve improperly flashing the deck, so rot might develop at the junction of the ledger board and the exterior wall; failing to anchor the deck to the house, making it prone to pull-away and collapse; improperly installed or missing rails that make the deck unsafe; building the deck so that there is wood to soil contact which will, over time, cause decay. The photo below is a good example of that problem. Wood to earth contact, over time, causes rot.
And, in a small effort to encourage people to build better decks, I am including this link to a video that I produced on the topic of installing proper deck flashings.