The Research Sprints program offers faculty partners the opportunity to collaborate intensively and exclusively for one week with a team of librarians to achieve significant progress on research or teaching projects. This longitudinal study extends previous immediate and short-term assessments by interviewing Research Sprints participants at two research-intensive institutions 2-4 years after their concentrated week. The authors evaluate the enduring impact of the program on the participants' projects, research/teaching practices, and relationships with the library. Participants report achieving project goals, improved skills and student success, and greater awareness and appreciation of librarians' work.