For the last few years, there has been a large volume of research on Peer-to-Peer (P2P) system, resulting in many hybrid P2P models. This model is important to keep a high available SP because all P2P overlay traffic will be routed via the SP. Main purpose of this paper is to improve SP's availability for OPs so that the system selects the peer with the potential to go the longest without needing replacement. In order to achieve the goal, we study a peer's availability prediction based on analysis of SP's characteristics and past behavior. Based on these, we propose various replacement policies and evaluate them through experiments. This paper can improve the resilience of the system by improving the availability of SPs selected by OPs. Second, we analyze inherent SP's characteristics and its past behavior and discuss which factors affect the performance of the system. Finally, we show that predicted residual lifetime can help us understand the benefits of replacement policies.