Caching the content closer to the user equipments (UEs) in heterogenous cellular networks (HetNets) improves user-perceived Quality-of-Service (QoS) while lowering the operators backhaul usage/costs. Nevertheless, under the current networking strategy that promotes aggressive densification, it is unclear whether cache-enabled HetNets preserve the claimed cost-effectiveness and the potential benefits. This is due to ۱) the collective cost of caching which may exceed the expensive cost of backhaul in a dense HetNet, and ۲) the excessive interference which affects the signal reception irrespective of content placement. In this talk, we discuss these significant, yet overlooked, issues, showing that while densification reduces backhaul load and increases spectral efficiency in cache-enabled dense networks, it simultaneously reduces cache-hit probability and increases the network cost. We then introduce a caching efficiency metric, area spectral efficiency per unit spent cost, and provide quantitative insight on how much of the content library needs to be cached in the small-cell base stations. Based on our analysis we further draw some practical conclusions on the range expansion, which is known to be of substantial value in wireless networks, and whether it can make up for the caching inefficiency.