As LaTeX continues to serve as the tool of choice for writing technical documents, users often transition from short articles and reports to more complex and extended projects such as theses, books, manuals, and collaborative research papers. Managing these larger projects requires not only a sound understanding of LaTeX’s structure but also effective strategies for modularization, error handling, and content organization. This chapter is designed to guide readers through the process of working with large LaTeX documents in a scalable and efficient way.