There is no numbered scale for cricket memorabilia, and the thing that most decides its worth is not condition at all.
The first assessment is not condition
Match-worn, match-issued or replica. Three objects, three prices, and the most common serious misdescription in the category is a replica called match-worn. The three words.
If you cannot establish which you have, the word is replica or unverified.
Then provenance, on its own ladder
Present at the signing with a photograph · obtained at a known event · a certificate from a named issuer · a previous owner's word · unverified.
A certificate is worth exactly its issuer's reputation. Show the name.
Then condition, separately
Shirts — pilling, sweat staining, pulled threads, cracked print, lifted numbers, whether washed. Bats — face marks, edge damage, cracks, repairs, re-gripping, whether used. Caps and helmets — sweat staining, shape, lining. Paper — creases, tears, pinholes, foxing.
Signature fading belongs in the condition half, said plainly and photographed in neutral light. Describing it.
Why a single number fails
Because a mint replica and a stained match-worn shirt would score the same and are nothing like each other. The categories matter more than the scale.
Questions people ask
Does washing a match-worn shirt change the grade?
It changes the object, and it must be declared.
Is an unverified item gradeable?
Its condition is. Its provenance is simply unverified, which is an honest state.
Can I say "looks genuine to me"?
Yes — it is plainly an opinion, and opinions are fine.