In this paper, one of the most important parameters in performance evaluation and protocol design of wireless networks, Link Excess Life (LEL), is investigated. An analytical model for LEL is proposed and evaluated. Evaluation of the proposed model leads to the first closed form expression for the excess life PDF. The closed form expression affords ease of further evaluations, e.g., an interesting result is that the average excess life is infinite for the proposed model. The effect of relative velocity distribution on the link excess life PDF is also investigated. The superposition property of LEL is mentioned and used to explore a systematic method for evaluation of the effect of stationary or pausing nodes on link excess life as well as a general method to approximate the link excess life PDF for various relative velocity distributions. Moreover, the effect of the buffer zone on the link excess life PDF in topology control is also investigated analytically. A simulation framework is developed and extensive simulations are performed to validate the results.