Edge Computing is a scheme to improve the performance, latency and security guidelines for IoT applications. However, edge deployment of an application also comes with additional complexity in management, an increased attack surface for security vulnerability, and could potentially result in a more expensive solution. As a result, the conditions under which an edge deployment of IoT applications delivers a better solution is not always obvious. Metrics which would be able to predict whether or not an IoT application is suitable for edge deployment can provide useful insights to address this question. In this paper, we examine the key performance indicators for IoT applications, namely the responsiveness, scalability and cost models for different types of IoT applications. Our analysis identifies that network centrality of an IoT application is a key characteristic which determines whether or not an IoT application is a good candidate for edge deployment. We discuss the different measures of network centrality that can be used to characterize applications, and the relative performance of edge deployment compared to centralized deployment for various IoT applications.