What affects does not washing shampoo and conditioner out properly have on the hair?

Not washing shampoo and conditioner out properly can lead to product buildup on the hair and scalp, resulting in a greasy or weighed-down appearance. This residue can also clog hair follicles, potentially leading to scalp issues like dandruff or irritation. Over time, the hair may become dull and lifeless, losing its natural shine and bounce. Additionally, improper rinsing can hinder the effectiveness of subsequent hair care products.