I don't think everything has to be parented to a hip. You can parent items/objects to almost anything in a scene. If you want a watch to follow a wrist, you'd parent the watch to the wrist (or more specifically, the bone used for the wrist). If you parented the watch to the hip, then you'd get some funky disconnects when you moved your figure.
I often parent the eyes to a camera, so that when the figure is moved, the eyes will stay locked to the camera.