Despite the analogy, this may actually be a stupid question... Of course comparing a sale price with current & past sales gives you a rough idea about what the market value is - but are there any more concrete ways of assessing a unit's value? When you have a plot of land with a property, this gives you a reasonable starting point in determining the value of the house through accessing a council land valuation and then making any additions to that value for the dwelling. Generally I try to buy a property for a price that is over 75% of what the unimproved land value would be. But obviously this formula doesn't apply to units. For example (figures are not accurate): - 90sqm unit in Ryde - Approx land value is $700sqm - 90 x 700 = $63000 ...and good luck trying to find a unit in Ryde for that price. What formulas and things to consider do you apply in determining the value of a unit?