Introduction:
When preparing for UPSC exams, it is crucial to solve previous years' papers as part of your preparation strategy. However, the question remains whether to attempt them in one sitting or break them into sections. Let's analyze the pros and cons of both approaches to help you make an informed decision.

Attempt in one sitting:
Attempting previous years' papers in one sitting has its advantages:

1. Time management: Solving the entire paper in one sitting helps you practice time management skills, which are essential during the actual exam. It allows you to get accustomed to the time constraints and develop a strategy to allocate time to different sections.

2. Exam simulation: Attempting the complete paper in one go simulates the actual exam environment, helping you experience the pressure and stress that you may encounter during the UPSC exam. This helps in building endurance and mental resilience.

3. Identifying strengths and weaknesses: Solving the entire paper at once helps you identify your strengths and weaknesses across different subjects and sections. It gives you a comprehensive view of your performance and areas that require more focus.

Break into sections:
Breaking the previous years' papers into sections also has its merits:

1. Focused practice: By breaking the papers into sections, you can allocate dedicated time to each subject or section. This allows for more focused practice and deeper understanding of the topics covered in that section.

2. Progressive learning: Solving papers section-wise enables you to gradually progress from easier to more challenging questions. This helps in building confidence and competence in tackling different types of questions.

3. Targeted revision: Breaking the papers into sections allows you to revise specific topics or subjects that you feel require more attention. This targeted revision helps in reinforcing your understanding and improving your performance in those areas.

Conclusion:
In conclusion, both approaches have their merits, and the choice depends on your personal preferences and study style. If you prefer a holistic approach and want to practice time management skills, attempting the papers in one sitting would be beneficial. On the other hand, if you prefer focused practice and targeted revision, breaking the papers into sections would be more suitable. It is advisable to adopt a combination of both methods to ensure comprehensive preparation for the UPSC exam. Remember to analyze your performance after solving the papers and work on improving your weak areas.