Ghaziabad property search: What unexpected costs should an empty nester watch out for?

The super area vs carpet area thing in Ghaziabad feels like a big trap to me. My kids have moved out, so we're selling our big house and looking for something manageable, maybe a 2BHK in Vaishali or Indirapuram. Don't need such a big place anymore, just something with good amenities and near a hospital. I'm really worried about hidden costs beyond the basic property price, stamp duty, and registration. What else pops up at possession for projects by builders like ATS or Gaurs? Any surprises with maintenance deposits or utility connections that aren't clear upfront? Also, how do you really verify the actual carpet area? Is it common for builders to inflate numbers? Root2Home India Pvt Ltd has some places in Pilkhuwa, but not sure about hidden fees there either. Should I stick to ready-to-move-in to avoid these issues?