Patwari living: the real cost beyond EMI

The real cost of living in Patwari, Noida Extension, is often higher than what builders project. From my experience, maintenance charges and RWA fees can seriously impact your monthly outflow, sometimes adding 20-30% to the EMI. Builder brochures rarely detail these, aur baad mein pata chalta hai. Plus, water supply and power backup costs are often extra. Buyers should factor in these 'hidden' charges, especially for societies without OC. This directly affects your overall ROI. Any similar experiences ya tips on negotiating these post-possession?