Buying tubes...do they vary???

At this point there IS no NOS. Anyone claiming they are selling NOS is not telling the whole story.
Like that great 427 Cobra sitting in a barn for 50 years and you find it and buy it for $200. Ain't real. Fantasy, or a lie.
I really would never believe anyone trying to sell NOS (pre 1980) anymore. PERIOD.
(I do believe there are new old tubes hidden away in stashes at various folks homes and garages. Those are not gonna be for sale until the dudes are dead.)

 I guess I always thought these supposed caches of 1950's etc. tubes were mostly slightly used tubes that tested out as basically new stock.  The thought that all of the modern tube vendors could have such a wide variety of NOS tubes in such numbers in stock is rather unrealistic.  Perhaps those valves should be called SUNOS.

Elizabeth. you have to understand that back in the 40's, 50's, and 60's there were tens of thousands of new tubes produced. Not just for people's TV;s and radios, but for medical equipment and for the military of which great supplies where produced but not all used. There is a vast supply of those old tubes out there that never saw daylight outside the boxes they were put in. Call Andy Bauman of VTS. He will give you the REAL skinny on what is out there, NOS......

@mr_m , you’ve brought up an interesting subject. I like to deal with Andy of VTS not only for his high quality tubes and advice, but also to hear about his experiences in the electronics/tube world. He once told me about after WW II and Korea, the techies would grab all the tubes they could gather and ship them home. The tubes came from radio installations and anywhere electronics were used; that includes the enemy and the Allied forces supplies. Tubes were even scooped up from the battlefield.
I once ordered a rare Amperex tube from Andy, he only had one and said he would look for it on the top shelf of an area he hasn’t used for a while. I received the order and the box was dirty, faded, and tattered, just like it had been through a war. The tube inside was perfect and had incredible low noise.

There is a vast supply of those old tubes out there that never saw daylight outside the boxes they were put in.

Think of all the different scenarios where tubes may have come from.

But, I agree with @elizabeth that there are many, many tubes being sold as NOS that were lightly used and taken from electronic devices. If they test well, they are called new old stock. It’s funny how many NOS tubes come in a generic white box.

Love it when a post takes off! Thanks all for the wonderful responses!