Analysis of degradation data can provide information about the lifetime of highly reliable products, if there exists a product characteristic whose degradation over time can be related to reliability. To obtain a precise estimator of a product mean time-to-failure, one practical problem arising from designing a degradation experiment is: how long should the experiment last? This paper proposes a termination rule to determine an appropriate stopping time of a degradation experiment. A case study of an LED product illustrates the method. The proposed procedure is computationally simple and provides reliability analysis for on-line real-time information of the product lifetime when the termination time is determined.