Choosing an optional subject for UPSC Mains involves several factors, including personal interest, academic background, and scoring potential. Candidates should assess their strengths in different subjects and consider the availability of study resources. Prior experience or familiarity with a subject can enhance understanding and retention. Aspirants should also review previous years’ trends to identify which subjects yield higher success rates. Ultimately, selecting a subject you are passionate about can motivate consistent study and engagement. Consulting mentors or peers with prior experience can further provide insights, helping aspirants make informed decisions regarding their optional selection.