This article is motivated by the desire to integrate and expand two literature streams, one that models effects of prior information technology (IT) use and habit strength on continued IT use and another that studies how to apply such models to IT that are used in a characteristically sporadic manner. We find that joint predictions of continuance intention, prior IT use, and habit strength within our research model are superior to subsets of the model across the extended range of usage frequency we studied. However, subsets of the model can also provide reasonable predictions where all measures are not available.