This paper tests a new predictive model of IT acceptance in conditions where use is characteristically sporadic. The model utilizes cognitive constructs from the well-known technology acceptance model (TAM)  in combination with habit and a new construct measuring perceived regularity of use. Initial tests indicate that the model explains several important effects of regularity and predicts substantially more of the variance in continuing acceptance than alternative models.
Wilson, E. Vance; Mao, En; and Lankton, Nancy K., "Predicting Continuing Acceptance of IT in Conditions of Sporadic Use" (2005). AMCIS 2005 Proceedings. 267.