<p>Repeated insertion-removal processes weaken the mechanical and electrical performance of electrical connectors. A combined experimental and numerical investigation is conducted for the contact behavior degradation. Multiple insertion-removal tests are conducted on the pin-socket assembly of electrical connectors to measure the evolution of insertion force and electrical contact resistance (ECR). A finite element model of the pin-socket assembly is established to predict the effect of wear on the insertion force, contact area and ECR, in which the friction-energy-based wear model is employed. The rough surface profile described by the Weierstrass-Mandelbrot (WM) function is considered in the modeling. The numerical model is validated against experimental data. The results show that the dominant mechanism is abrasive wear, accompanied by coating removal, debris formation, and oxide film generation, which leads to a peak ECR around 6,000 cycles. Parametric studies reveal that increasing the socket diameter constriction raises both insertion force and ECR. In addition, a large surface roughness decreases the effective contact area and significantly increases ECR. The results provide insight into the mechanical and electrical degradation of electrical connectors, which offers practical guidance for structural optimization in engineering applications.</p>