Intelligent Energy efficiency is an important research topic for ad-hoc Wireless Sensor Networks (WSN). Power saving makes it possible to guarantee basic levels of system performance, such as connectivity, throughput and delay, in the presence of both mobility-immobility and a large number of sensor nodes. A large variety of approaches for intelligent energy-efficient schemes have been proposed in the literature focusing on different performance metrics. This article presents a comprehensive survey of recent energy-efficient schemes in ad-hoc wireless sensor networks, the application of which increases nodes’ lifetime and thus, network connectivity and survivability.