What are used tubes worth ?

Tubes, not like fine wine, are not worth the trouble of using. Look for new, which avoids stress.

Have them tested and publish the results("minimum" specs, compared to actual, at least) in your description(ie: on eBay). That way bidders will have an idea of how much life to expect from the tubes. (http://www.ebay.com/itm/Hickok-Tested-Used-RCA-6SN7-GT-Amplifier-Tube-Gray-Glass-/141556068170?pt=LH_DefaultDomain_0&hash=item20f5662f4a) If it's worth it to you; these guys can test them: (http://tctubes.com/tube-testing-service.aspx)

I can understand where everyone is coming from in this thread...

That said, it's also the reason I get fantastic tubes at such reasonable pricing. As you can see here, people look down their noses at used tubes.

Apart from some of the upper echelon products introduced in the past 5 or so years, older tubes simply perform better than newer variants. By that I mean, both sonically, and when it comes to longevity. In fact, some old tubes seem to defy logic when it comes to how long they'll last.

Claiming NOS, whether true or not, whether known or not, spikes the price folks are willing to pay. The converse also proves true. Obviously the same holds for newer production tubes, as well.

No sleight to anyone who drinks off the top shelf. As for me, I'll buy the same sonics at a huge discount. Use it to your advantage.

I have invested in a Beck RM-1 tube tester. Although only the ears can be the final test of a tube's musicality, it should help avoid bad tubes, at least.

Maybe something on Audiogon for the rest of the world not much.