Most disappointments here are not about condition. They are about getting a different edition, or a set with a gap in it.
Ask for the publication page
Publisher, imprint, language, printing. Held still, readable. It is the fastest way to know exactly what is being sold, and a seller with a legitimate copy loses nothing by showing it.
Ask for the volume numbers
Not "most of the set" — the actual numbers, read out or shown with the spines facing the camera. Gaps in a run are expensive to fill and a buyer who discovers one after delivery has a real grievance.
Then condition
- Spines — creasing, cracking, and whether a book has been read flat
- Page edges — foxing, yellowing, damp
- Covers — bends, scuffs, price stickers
- Dust jackets, where the edition had one
On official and unofficial printings
Ask where the seller got it and what the book carries. A seller who answers specifically, and who shows the publication page without being asked, is the one to bid with.
No video call settles this question. If the edition is the reason you are bidding, weigh the price against how much the seller has actually been able to show — and if something is being sold as unverified, pay unverified prices.
Figures
Ask for every face of the box, the contents visible, and whether it has been displayed in sunlight. The toys guide goes further.
What protection covers
A different edition than described, missing volumes, undisclosed damage, or an unofficial printing sold as official: not as described, seven days from delivery. The last one is also worth reporting.
Questions people ask
Is a reading copy worth buying?
Yes, at reading-copy prices, and plenty of people prefer them.
What is an omnibus?
Several volumes bound as one. It is a different item from the singles, so check which you are bidding on.
Does yellowing matter?
To value, yes. To reading, no. Ask for the page edges shown.