This chapter provides a detailed overview of logging and inspection techniques crucial for evaluating and maintaining well integrity across all phases of a well’s life. It begins with cement evaluation tools—such as Cement Bond Logs (CBL), Variable Density Logs (VDL), and advanced ultrasonic imaging—that assess the quality of cement bonding and detect zonal isolation failures. The chapter then covers corrosion logging methods, including electromagnetic thickness tools and mechanical calipers, which identify and quantify internal and external metal loss in casing and tubing. Leak detection technologies are also explored, including temperature logs, acoustic/noise logs, fluid identification tools, and chemical tracers. These techniques are essential for pinpointing the depth and nature of leaks behind casing or within annular spaces. The chapter further addresses routine wellhead inspection and maintenance practices that ensure surface barrier components remain functional. Finally, the chapter introduces Risk-Based Inspection (RBI), a strategic approach that prioritizes monitoring and diagnostics based on the likelihood and consequence of failure. This framework enables efficient resource allocation and enhances long-term well integrity management. Collectively, these tools and strategies support safe operations, timely intervention, and regulatory compliance.