Today's smartphone users often use several mobile messaging services alongside each other, even though they typically offer the same features and functionality. Where previous studies have focused on how and why users permanently abandon mobile messaging services and switch to new ones, this study examines the degree to which smartphone users keep switching back and forth between multiple services, and the factors that influence this temporary switching behavior. We used an exploratory research approach in a longitudinal diary study combined with semi-structured interviews. We found that temporary switching behavior is influenced by technological affordances, contextual factors, individual preferences, and the type of conversation. Both positive and negative impacts were identified within these aspects, with some having an indirect influence, revealing the complexity of temporary switching behavior.