What to ask when buying used speakers?

I agree with many others, forgoing used is silly especially with the lead time issues some manufacturers are still faced with.  You simply have to feel out the seller and let your spidey sense be your guide.  I'm batting 1.000 with my 3 purchases, of which 1 was a high-dollar-never-saw-them-in-person transaction.  I honestly wasn't worried in the least after talking to the seller and (admittedly) stalking him a bit once I had a name.  

Unrelated - someone brought up "pet free" what exactly are people afraid of with pets?  Is it cats and speaker grilles in particular?  

@soix I have avoided posting any budget or brand names to prevent the discussion from devolving into specific speaker recommendations. The feedback here has been very useful and I would say mostly in favor of used purchases with proper due diligence. Thanks everyone. 

I've owned 3 sets of Magnepans and a current set of Acoustat speakers,  all purchased used. 3 of those sets were sight unseen.  The 2nd pair I purchased from ebay, they were damaged which may have been a result of shipping.  The seller had me send the speakers to Magnepan for service at his expense. 

There are still honorable people out there, just be careful and selective. 

Enjoy the Music

Lots of good advice here so far! If buying from a reputable dealer I wouldn't worry honestly, assuming they have a good return policy. If buying from a dealer, I would still like to know if the speakers were modified in any way. This can make them sound different than what you are expecting, but it can also lead to problems in the longer run. I've seen speakers with changes to the crossover or drivers which would put a lot of stress on the other drivers, but also once bought a pair where the previous owner drained all the ferrofluid from the tweeter to 'make them sound more detailed'.

I buy all my speakers used and I do always expect to have to do some small maintenance, such as glueing a surround or replacing ferrofluid. If you don't mind doing something like that with some pairs, there are real gems to be found for very little money (:

@mtbiker29 cats destroy grills, but I've also seen surrounds and cones with claw marks.

Speakers (and other components) I  have almost always bought dealer demo or used from a reputable dealer.  They have always stood behind all details of the product and sale.  No worry a that product had been misused.  Twice when I bought something i had not been able to demo and did not like the product, the dealers took them back within 30 days no hassle with full refund or very minimal fee.  My years of building relationships with dealers who I trust and now trust me, has proven very valuable.  I now get great deals and service.  I like supporting dealers.