Criticality analysis is a fundamental tool in the oil and gas industry to ensure the efficiency and safety of equipment. This paper presents a comprehensive literature review on current methodologies for identifying safety critical equipment (SCE) and critical equipment (CE). The review begins by discussing the initial step of identifying SCE, followed by the identification of CE. Various methodologies are examined, ranging from simple, quick screening techniques to complex, quantitative analyses. Simple methodologies are often used for initial assessments, while complex methods are applied to equipment posing high risks that require detailed, quantitative calculations. The review highlights the strengths and limitations of each approach, providing a comparative analysis of their effectiveness in different scenarios. Finally, the paper suggests a structured methodology for developing maintenance tasks tailored specifically for SCE and CE, ensuring optimal maintenance strategies that enhance safety and operational efficiency. This review aims to guide practitioners in selecting appropriate methodologies for criticality analysis and maintenance planning in the oil and gas sector.