Recent works on Information Centric Networking enable the exploitation of the caching resources in the new generation of routers (Content Routers or CR). So far, only a basic Least Recently Used (LRU) strategy implemented on every CR has been proposed. More generally, the research community lacks methods for analyzing and evaluating caching policies (other than LRU) in generic multi-cache topologies. In this paper, we provide a model that approximates the hit-ratios of any multi-cache topology for the Least Recently/Frequently Used (LRFU) caching policies, which consist of a spectrum of policies based on a trade-off between recency and frequency. We also present a way to approximate the perforamnces of the network of caches when the input traffic changes. The approximation results can be used to decide suitable policy for CR at different positions in the network topology. With appropriate policy for each single CR, we are able to improve the performance of the whole in-network caching system.