The 15th Astrobiology Graduate Conference (AbGradCon) was held at the University of Utah this past July. AbGradCon is a unique academic conference that is organized solely by early career scientists for other early career scientists. Every year, graduate students and postdocs gather to present their research through oral and poster presentations, take part in public outreach events, and gather informally to forge connections with their peers. This provides the opportunity to create and strengthen interdisciplinary and international networks between early career astrobiologists who will be leaders of such research in the years to come. Indeed, after 15 iterations, many of the alumni of the earliest AbGradCon meetings have gone on to become senior scientists and principal investigators. As organizers of the 2019 meeting, we feel that AbGradCon can serve as a robust model for other student-led meetings in any discipline. Here, we reflect upon the successful changes that have been implemented over the years, how current conference activities align with our goals, and the future challenges that AbGradCon faces as we look forward to the next 15 years of the conference.