This paper presents the robustness and performance anal- ysis of the Controlled Greedy Sleep algorithm, which was designed to provide k-coverage in wireless sensor networks. The aim of this algorithm is to prolong network lifetime while ensuring QoS requirements in a dynamic manner. We investigated how the network can be strenghtened to im- prove performance characteristics, and how this algorithm ensures graceful degradation (i.e., how the network will pro- vide less accurate measurement data as sensors become un- available). We also test the robustness of the algorithm by measuring the effect of message loss due to communication errors. We compare the results to those of a very known and frequently used random algorithm. Our performance tests are based on simulations results.