Beyond RERA: Uncovering legal details for my first home

Budget finalised, loan pre-approved — now stuck on which sector. I'm looking at a few properties in Sector 24C, mostly resale flats. Honestly, the legal verification part is giving me major anxiety. My lawyer mentioned checking the encumbrance certificate for the last 30 years, not just 13. I had no idea that was a thing! Also, RERA check isn't just about 'approved' status, right? What about the specific project details matching? Are there any other crucial documents or steps I absolutely shouldn't skip? What was your experience like with title searches? Did anyone face issues with older properties or properties that changed hands multiple times? Any specific red flags to watch out for during these legal checks in Chandigarh? Don't want to regret anything later.