Sometimes the item was once part of a set and the rest of the set is missing
Sometimes the item is a set and it is missing additional pieces
Sometimes a piece appears used or may even be used
Sometimes pieces have makeup, dust or deodorant or similar on it from being tried on or dropped on the floor. Makeup and deodorant can be removed without washing. If you're not sure how to remove it, simply look at the interior tag that says the material of the garment and Google search "How to remove lipstick (or whatever it is) from cotton (or whatever material) without washing"
We try to weed out major damage but it is not always possible to catch 100%.