A shoe (606) degradation sensor (1012, 608) assembly includes a first sensor (1002) disposed in or proximate to a material layer of a shoe (606) between a foot space and an outer surface of the shoe (606). The material layer changes in at least one physical property with degradation to the shoe (606), and the first sensor (1002) is configured to indicate the changing physical property of the material layer thereby indicating a degree of degradation to the shoe (606).