What to ask when buying used speakers?

I prefer sealed enclosure speakers because of possible insect or rodent damage through the speaker port.     Also, more common brands where it is possible to get replacement parts.

You hit the main issues right on the head.... age for decaying caps and speaker foam.... both of those issues can be addressed though if the price is right and you know what you are doing. High end speakers around 15 years old may start having issues but not necessarily. Ask about cosmetics, distortion, and If they are the original owners. I've bought several used sets of speakers and had to refoam one pair after a short period of time but the seller wouldn't have known it would happen. Some people want to know if the seller was a smoker or not.

Here's my list of questions:

- Have you ever played the album The Big Sound of the Drags at over 110 SPL?

- Have you ever tried to troubleshoot a "no sound" condition by maxing out the volume control on the preamp, then switching sources until something made noise?

- Ever left your system unattended for hours with someone under 25 at home?

- Ever made a water/smoke/vandilism claim on anything in the room were the speakers reside?

- Ever use this room for the kitty potty area, or to housebreak a dog, skunk, or Tasmanian Devil?

There's more, but thought this would be a good start.

I would ask if they were broken in yet or were still relatively new? That way I'd know what to expect from the sound over weeks or whatever.... 

Will you take 50% of your asking price……