Originally Posted by
HillRider
Hmmm, this could be more of a problem than you think. "Excellent condition" for a cassette is impossible to tell by inspection and "one season" could have been 100 miles or 5000 miles. Even with a new chain you might have skipping problems on the cogs the former owner used the most. I hope this cassette is very cheap or you have return privileges because you might be buying a new one after trying it.
+1 I wouldn't buy a used cassette unless the price was a tiny fraction of the price of a new one. By tiny, I mean much less than 25%