Deterministic record and replay is fast becoming a vital technology in desktop and server computing environments. Yet, the applicability of this technology to computation run on small, mobile devices such as cell phones has not yet been explored. We argue that there are several potential uses of replay that are especially beneficial when applied to mobile phones: dual execution on cloud or cloudlet computers to reduce latency and possibly phone energy use, operation shipping for file synchronization, and offloading of expensive security and reliability checks to remote servers. In this paper, we explore these potential uses, as well as some of the unique challenges posed by implementing replay on phones. 2.