Power management techniques for mobile appliances put the components of the systems into low power states to maximize battery life while minimizing the impact on the perceived performance of the devices. Static timeout policies are the stateof-the-art approach for solving power management problems. In this work, we propose adaptive timeout policies as a simple and efficient solution for fine-grained power management. As discussed in the paper, the policies reduce the latency of static timeout policies by nearly one half at the same power savings. This result can be also viewed as increasing the power savings of static timeout policies at the same latency target. The main objective of our work is to propose practical adaptive policies. Therefore, our adaptive solution is fast enough to be executed within less than one millisecond, and sufficiently simple to be deployed directly on a microcontroller. We validate our ideas on two recorded CPU activity traces, which involve more than 1...