Consumer health information behavior (CHIB), which encompasses a person's health-related information needs and the activities in which they engage in order to look for, manage, and use information related to their health condition, impacts a person's ability to manage and cope with a disease. Although CHIB has been found to be both dynamic and situational, very few studies have undertaken to study this phenomenon as a process that unfolds across time. This paper reports results from a longitudinal, mixed-method study of the information behavior of people with type 2 diabetes. This study aimed to discover this group's information needs and information seeking practices, the factors that motivate or impede their information seeking and use, the sources and types of information that they find useful, and how all of these changed across time. This paper focuses on results related to participants' perceptions regarding the usefulness of different sources and types of diabetes-related information. The findings indicate that important changes took place in participants' perceptions regarding the usefulness of information as their disease progressed, as their attitudes changed, and as their awareness of their information needs changed. A suggestion is made to extend the definition of information behavior to encompass an earlier state (“incognizance”) in which a person has not yet become aware that he/she has an information need and is, thus, less able (or unable) to recognize the potential relevance and usefulness of information. Implications for the important role that researchers and information professionals can play in helping to mitigate incognizance and its potentially devastating impacts are discussed.