Comics have one of the oldest condition vocabularies in collecting, and a numeric scale that sits on top of it.
The scale
Professional grading runs 0.5 to 10, with descriptive names attached to the bands — poor, fair, good, very good, fine, very fine, near mint — and most of the money sits in the top third.
Good means worn, as it does in books. It is the rung that catches every newcomer.
What decides the grade
The spine, above everything else — ticks, stress marks, creases, and whether the book has been read flat. Cover gloss and colour. Corners. Page colour, stated alongside the grade and affecting price in its own right. Flatness, and whether anything has been pressed.
Restoration changes what the book is
Any work done — colour touch, tear seal, piece replacement, trimming — is recorded separately from the grade, and it must always be declared. A restored book described as original is the claim that ends sales in this category.
Pressing is treated separately again, and opinion is divided on it. Declare it either way. Describing comics.
When grading is worth it
For keys and high-grade books where the slab adds more than the fee and the wait cost. For a reading copy it never is.
If you do not grade
Give a band and say so: "I would call this very fine, but I do not grade." That is honest, defensible, and buyers accept it.
Questions people ask
Does page colour affect the grade?
It is stated alongside it and it affects the price.
Is a restored book worthless?
No — it is a different object, priced differently, and sold honestly.
Can a pressed book be graded?
Yes. Declare the pressing either way.
More: buying comics, what they are worth.