The problem addressed by this study is the high attrition rate of veteran public secondary teachers due to a multitude of challenges and changes faced throughout their tenure in an education career. The purpose of this qualitative descriptive phenomenological study was to explore the lived experiences of veteran public secondary teachers to discover what challenges and changes caused them to leave long-term careers in secondary education in South Dakota. Eight participants responded to social media invitations for a one-on-one semi-structured interview, and three participated in the optional focus group. Using Prochaska and Norcross's (1980s) transtheoretical model of change, the findings of this study indicated that veteran public secondary teachers found the most important factors in their decision to leave education were administration and mental health. Veteran public secondary teachers shared that student behavior is the greatest challenge in education. The most impactful evolutions in their tenure are technological advancements and student attitudes toward education. Practice recommendations include (1) developing and communicating clear expectations for excellence among students, staff, and parents; (2) developing and enforcing a behavior schedule with written agreement from parents, students, and teachers; (3) technology privileges should be protected with clear rules and expectations across the district; (4) curriculum should be updated to meet the needs of the 21st-century student; (5) administration must strive to develop strong relationships with their staff; (6) a teacher's mental health should be considered when developing administrative expectations, class rosters, and course assignments; and (7) mental health resources should be provided and encouraged to be used by all staff within the school district. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]