In a category this broad, the useful question is not about condition. It is about what exactly you are being offered.
The question
"What makes this one different from an ordinary one?"
Edition, run, variant, year, marking, provenance. A seller who can answer precisely knows the object. A seller who answers "it's rare" has told you nothing you can check.
Then
- Numbering and edition size, shown
- Every face of the box, if it is boxed
- Completeness — certificates, inserts, stands
- The piece turned slowly, under even light
- Any damage, shown rather than described
On reproductions
Ask directly whether the piece is an original issue or a later reproduction, and ask how the seller knows. Both are sellable; only silence is a problem.
If the seller says they cannot be certain, that is an honest answer — pay an uncertain price.
What protection covers
A reproduction sold as original, missing pieces described as present, damage not shown, or a different item than the one on camera: not as described, seven days from delivery.
Questions people ask
Is a numbered edition always worth more?
Not always — a large numbered edition can be common. Ask the edition size, not just the number.
Does the box really matter?
For anything issued boxed, often more than the object. Ask for the box shown on all sides.
How do I value something I have never seen before?
Ask the seller what they paid attention to, and bid what it is worth to you. How much things are worth.