A purple slip dress is simple and useful. It works as a standalone piece in warm weather or as a layering foundation when it gets cold. The fabric is usually jersey or a soft cotton blend that moves easily. The fit tends toward minimalist. Thin straps. A simple neckline. Knee length or just below. The straightforward cut means you can layer it under shirts and jumpers without creating bulk. Or you can wear it alone with a denim jacket or cardigan thrown over it. Purple is a colour that works with most existing wardrobe pieces which makes this inherently versatile. Some have minimal side slits for movement. Others stay completely simple. The construction needs to be sturdy enough that the thin fabric does not feel insubstantial. These are the purple slip dresses that prove sometimes the most useful things are the simplest ones.