It is the difference between a client who wears their unit comfortably for years and a client who develops folliculitis, yeast overgrowth, or contact dermatitis within weeks. We see it more than we should. A client invests in a beautifully constructed prosthesis. The fit is good. The hair looks natural. She loves it. And then three weeks later she is calling because her scalp is itching, inflamed, and reacting in ways nobody prepared her for. The prosthesis did not fail her.