Providing universal coverage and barrier-free access to ID systems is one of the three pillars of the Principles on Identification for Sustainable Development and is vital to achieving Target 16.9 of the Sustainable Development Goals (SDGs), to "provide legal identity for all" by 2030. Large-scale registration campaigns can help achieve this objective by making identification accessible to large segments of the population within a short timeframe and by often being able to reach individuals and population groups who, for various reasons, face difficulties in obtaining IDs in the absence of concerted outreach efforts. Without sufficient planning, coordination, and the adoption of appropriate policies and measures for inclusion and building trust in the system, however, registration drives may be unable to boost the coverage of the system to achieve a critical mass and can thus became a waste of (public) resources, while exacerbating exclusion. This note aims to help practitioners learn from past efforts, promote the adoption of good practices, and reduce the risk of failure.