Stamp duty is one of the biggest up‑front costs in a NSW property transaction, but you don’t have to accept the first number Revenue NSW puts in front of you. In family deals, distressed sales, properties with serious defects and first‑home buyer threshold scenarios, a well‑prepared independent valuation can legitimately reduce or protect your duty position. This guide explains when valuations make a real difference, how the process works, and what to avoid so you stay on the right side of the rules.