To support school improvement, understanding the mechanisms that enhance teachers' engagement in professional learning activities within schools over time is paramount. The purpose of this three-wave longitudinal study is to examine the role of workplace conditions (school leaders' vision building and teams' shared goals), in supporting teachers' engagement in information sharing over time. To test the directionality of the relationships between the concepts, we analyzed survey data from 655 vocational education and training teachers in the Netherlands using a cross-lagged panel model. Results suggest that teachers' engagement in information sharing remains stable over time, and the results are indicative of reciprocity between goal interdependence and vision building. Mostly, the results hint at the complexity of the time-based relations involved in teacher learning in support of school improvement. Recommendations for future designs and methodologies to understand this complexity are discussed.