The Harwood Nail Salon uses a sign$-$in program for its patrons. First$-$time visitors receive a $10$ percent discount. When customers sign in on Tuesdays, they know that their visit comes with a free hand massage. Frequent visitors can receive all those benefits plus earn $50$ percent off a visit after $7$ visits. The Harwood Nail salon has created a marketing mix based on what type of segmentation?