Assessment is currently seen not only as a means to evaluate students' performance but also as a crucial tool for identifying learning needs and facilitating student progress, while simultaneously aiding teachers in refining their instructional methods. This paper presents findings from an in-depth study conducted through online surveys involving 149 teachers, consisting of 56 in-service and 93 pre-service educators. The aim of the study was to investigate the sources and activities that teachers prioritize and utilize in their teaching practices, along with their underlying motivations and methodologies. Notably, discussions emerge as a top source of importance and usefulness, while activities such as self-assessment, reflective practice, and constructive feedback are underscored as indispensable tools for both in-service and pre-service teachers. The driving forces behind teachers' preference for these top sources and activities center around their contributions to student learning, teaching practice, and the evaluation of student progress. Furthermore, the study highlights that these chosen sources and activities foster a positive learning community in the classroom. Teachers collectively voice reservations related to assigning grades, with standardized testing in particular receiving considerable skepticism. This research thus contributes to the ongoing discourse surrounding assessment practices, underscoring the importance of tailored and inclusive approaches that bridge the gap between assessment and effective pedagogy. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]