Introduction:
When preparing for any competitive exam, solving previous years' papers is an essential part of the study plan. It helps in understanding the exam pattern, identifying important topics, and practicing time management. However, aiming for 100% accuracy while solving these papers may not always be the most effective approach. Let's delve into the details and explore why.

Benefits of solving previous years' papers:
1. Understanding the exam pattern: By solving previous years' papers, you can get familiar with the structure and format of the exam. It allows you to understand the types of questions asked, the distribution of marks, and the time allotted for each section.

2. Identifying important topics: Previous years' papers help in identifying the recurring topics and concepts that have been frequently asked in the exam. It allows you to prioritize your preparation and focus on the areas that carry more weightage.

3. Practicing time management: Competitive exams are time-bound, and managing time effectively is crucial. Solving previous years' papers helps in improving your speed and accuracy, enabling you to complete the exam within the given time frame.

Limitations of aiming for 100% accuracy:
1. Time-consuming: While attempting to solve previous years' papers with 100% accuracy, you may end up spending a significant amount of time on each question. This approach might not be feasible, especially when you have a limited time for preparation.

2. Pressure and stress: Setting an unrealistic expectation of achieving 100% accuracy can lead to unnecessary pressure and stress. It may impact your confidence and hinder your overall performance in the exam.

3. Lack of coverage: Focusing solely on achieving 100% accuracy may result in neglecting other important aspects of the exam preparation, such as revising concepts, practicing mock tests, and analyzing mistakes. It is essential to have a balanced approach to maximize your chances of success.

Recommended approach:
1. Quality over quantity: Instead of aiming for 100% accuracy in every previous year's paper, focus on understanding the concepts and solving a sufficient number of questions from each topic. Emphasize on learning from your mistakes and improving with each attempt.

2. Time-bound practice: Allocate a specific time duration for solving each previous year's paper. This approach will help you simulate the actual exam conditions and improve your time management skills.

3. Regular revision: Along with solving previous years' papers, allocate time for revising the important concepts and topics. This will ensure a well-rounded preparation and enhance your overall understanding of the subject matter.

Conclusion:
While solving previous years' papers is undoubtedly beneficial for UPSC exam preparation, aiming for 100% accuracy in every paper might not be the most practical approach. It is important to strike a balance between accuracy and time management, focusing on improving your understanding of concepts and revising important topics. Remember, the ultimate goal is to perform well in the actual exam, and a holistic preparation strategy will contribute to your success.