This article reports on a longitudinal analysis of query logs of a web‐based case library system during an 8‐year period (from 2005 to 2012). The analysis studies 3 different information‐seeking approaches: keyword searching, browsing, and case‐based reasoning (CBR) searching provided by the system by examining the query logs that stretch over 8 years. The longitudinal dimension of this study offers unique possibilities to see how users used the 3 different approaches over time. Various user information‐seeking patterns and trends are identified through the query usage pattern analysis and session analysis. The study identified different user groups and found that a majority of the users tend to stick to their favorite information‐seeking approach to meet their immediate information needs and do not seem to care whether alternative search options will offer greater benefits. The study also found that return users used CBR searching much more frequently than 1‐time users and tend to use more query terms to look for information than 1‐time users.