Which test series is considered reliable for UPSC Prelims GS practice?

For the UPSC Prelims, Sleepy Classes, Vision IAS, Forum IAS, and Insights IAS are the most reliable test series.
Sleepy Classes is a top budget-friendly choice, costing around ₹3,999. It is highly reliable for its video solutions and current affairs integration, endorsed by toppers like AIR 2 Animesh Pradhan.
Vision IAS is the most popular for its strong current affairs linkage, with costs ranging from ₹8,000 to ₹12,000. It offers moderate-to-high difficulty and excellent syncing with their PT365 booklets.
Forum IAS is praised for its high-discipline "Simulators" and advanced difficulty, typically costing between ₹8,000 and ₹10,000.
Insights IAS provides a balanced, factual approach that is budget-friendly, ranging from ₹5,000 to ₹8,000.
Vajiram & Ravi is noted for its exam-aligned trend reflection, priced between ₹5,500 and ₹8,500.
While these coaching mocks help build stamina, they are supplements. Your primary benchmark must remain Previous Year Questions (PYQs) from the last 15–25 years.