Retrospective property valuations are one of the most powerful (and misunderstood) tools for managing capital gains tax. If you own or have inherited property in Sydney or Melbourne, getting the value right on a past date can save tens of thousands of dollars and protect you in an ATO review. This step‑by‑step guide explains when you need a retrospective CGT valuation, how it works, what it costs, and how to choose the right valuer.