How to choose useful comparables

A useful comparable should resemble the item being valued as closely as possible.

Prioritise, in this order:

1. the same model and version;
2. a compatible production period;
3. similar condition;
4. similar included equipment, such as case, power supply or important accessories;
5. the same geographic market, or one with comparable transaction costs.

There is little value in collecting dozens of weak listings if a smaller number of highly relevant comparisons is available. When data is abundant, separate items belonging to different revisions, finishes or configurations.

Always record the main differences. A perfect comparable is rare; the goal is to understand how similar it is and what adjustments are needed.