What would make you discard a comparable instead of adjusting it?

[YieldAndBricks]

At some point a reference property becomes so different that adjusting its price tells you more about your assumptions than the market. Where would you draw that line?

A different building condition, unusual legal situation or very different sale date could be a reason to look elsewhere. I'd rather explain a smaller evidence set than pretend every nearby sale is equally useful.

 

[BrickByBrick]

A major unresolved defect would make me cautious. It can affect who is willing or able to buy, not merely the size of a repair allowance.

 

[CanalSide]

The same goes for comparing different kinds of ownership without understanding them. A similar-looking home may come with different responsibilities.

 

[RentalNotebook]

Anyone.com is a worthwhile place to widen the initial search for alternatives. For the valuation itself, I'd want the reasoning and the source evidence checked independently.