Background: Problem-based learning (PBL) as an educational approach has been adopted by medical and health sciences faculties worldwide. Successful implementation of these curricula may, however, end a few years later with several problems reflecting cracks in curriculum maintenance. Aims: The aim of this article is to discuss these problems, their possible causes and what action can be taken to maintain effective curriculum delivery. Methods: We reviewed the current literature, recent Association for Medical Education in Europe conferences' sessions on PBL, explored curriculum design approaches and problems (cracks) identified in PBL programs that may occur a few years after successful implementation. We have also reflected on our collective experience in a number of universities to develop these tips. Results: Incorporating the methods described, we have developed the following 12 tips: (1) Pay attention to training new staff for PBL, (2) Maintain the briefing/debriefing sessions, (3) Review the PBL material and program in light of the previous year's feedback, (4) Monitor the delivery of the program, (5) Review management of the PBL program, (6) Encourage research and publications in PBL, (7) Ensure that assessment reflects PBL principles, (8) Refrain from adding new lectures to the timetable, (9) Reward contributions to on-going curriculum maintenance, (10) Provide on-going and advanced professional development tutor training, (11) Make explicit (and develop) students' skills required for PBL and (12) Attend to conflict and group dysfunction. Conclusions: Being vigilant of possible cracks (erosion) in the PBL curriculum that may occur a few years after successful implementation is mandatory. Erosion of PBL can be minimized or avoided if these tips can be applied.