Buying used or sight unseen speakers a bad idea?

I agree buying used is always a risk and yes, the sound can be degraded if the speakers are abused. I like to ask the seller if they are the original owner, if the speakers have ever been repaired and what amplifier was used with the subject speakers. I also make it a point to buy from sellers with all positive feedback. Even after all of that I recently purchased a set of speakers that arrived in very poor condition. Fortunately the seller took the speakers back and gave me a prompt refund. However, it cost me over $100 to find out the true condition of the speakers. A recent post here recommended observing how sellers conduct themselves on the forums. I think this is a good idea because it can tell a lot about a seller's character. This is good to know if you have a problem with a purchase.

Kira, Pictures mean very little when the seller is taking pictures of only the good side.

As far as listening I think you can only audition a speaker properly in your system and in your room. To me that is half the fun. Speakers can sound many different ways depending on the system and the room. I get enjoyment out of trying to get the most out of speakers. If you have several amplifiers and a closet full of cables you can get almost any speaker to sound good.