This chapter examines the critical integration of sustainability and cultural impact into cultural heritage preservation practices. It reviews the main conservation measures—restoration, curative conservation, and preventive conservation—as defined by key international standards (ICOM, UNE-EN). The core thesis posits that sustainability in this field must transcend the material preservation of assets to encompass a comprehensive framework of economic, environmental, and social responsibility. The study argues for incorporating sustainability criteria at every stage of the conservation process, from initial project planning and contracting to long-term management and monitoring. It highlights the importance of tools like Heritage Impact Assessments to proactively evaluate the consequences of interventions. Furthermore, it proposes a model where conservation strategies are shaped by predictable constants, such as the asset’s material nature, and critical variables like its use, management, and social context. The chapter concludes that achieving truly sustainable heritage conservation requires a holistic approach that balances traditional principles with contemporary sustainability demands, thereby ensuring the lasting value and relevance of cultural assets.