Why so many headphones for sale with less than 10 hours of listening time?

I've been in the market for a new pair of headphones recently, but have noticed that an unusually high percentage for sale are classified as "mint with less than 10 hours of listening time".  What gives?  How could anyone possibly make an accurate assessment on something with less than 10 hours involved?  Audeze is one of the brands I'm considering, but it seems like this is the one that has the most for sale with little time involved.  Could it be a comfort thing?  Any insight would be appreciated.