Get quotes, a sample and a test report; run a trial
The test report comes from the mill’s laboratory; the trial runs on your own machines.
A yarn quote comes with its validity date, a sample cone from the lot it was priced on, and the mill’s test report for that lot: count, twist, strength as CSP or RKM, evenness, imperfections and hairiness, with the Uster percentile if the mill works that way. Judge all three against the spec from step 1, not against each other, and run the cone on your own machines before you judge the price: a yarn that breaks on your frame is dear at any number. Ask which lot the cone came from and whether the bulk will come from the same one.
What a bad answer looks like: a sample cone from stock with no lot named, or a test report with no date and no laboratory on it, so nothing ties the cone in your hand to the lot you will receive.
