Teachers adapt their instructional strategies over time based on a variety of contextual constraints. In response to these challenges, teachers often have to make changes to their PBL approaches. While the literature has documented generally positive results of initial PBL implementations, less is known about the degree to which teachers adapt their usage of PBL over time. Some adaptations include a refined approach to teaching strategies, while others include significant diversions from the original PBL model. A better understanding of the changes teachers enact provides important insight as to fidelity and thus the expected learning outcomes of PBL. To address this gap, this research conducted semi-structured interviews with experienced K-12 educators who employed PBL over multiple years. In terms of preparing for PBL, themes that emerged from the interviews included more emphasis on reimagining the problem scope and design thinking. During classroom time, teachers described shifting perspectives in terms of the following: problem-solving skills over content knowledge, student control and teacher facilitation, and embracing failure. Relating to technology, teachers described more adoption trends towards collaborative tools, while also describing opportunities and challenges with digital literacy. Finally, teachers described strategic approaches to assessment in light of the ill-structured problems posed by PBL. Implications for practice and theory are discussed.