age doesn't really determine price.
i mean, it does. but not really that much.
condition, relevance, purpose, etc. are all major points, age is only a nice little fun fact about it as far as I'm concerned.
In relation to documents, you're roughly right.
Obviously, if there were thousands of similar documents printed and it's not that rare, it's not worth much.
But, due to the fact that it's from a very historic time in human history, that'll make it worth more.
And because of it's possibly historical information, it would be worth more the longer it survives.
In terms of old items, cars for example, and even paintings, silverware and clothing, the pricing can depend greatly on age, as something ancient will be worth a lot from an historical point of view. But something slightly more modern, or atleast, not ancient, would have worth depending on it's age, how many of the same things were made, if it has any historical significance, if it's in very good condition, and who made it.
Sometimes, silverware or old cars are worth a lot more than similar counterparts just because they were made by a very famous silversmith or car manufacturer.
I would suggest you get someone to give it a viewing and a pricing, see if you're comfortable with what it's worth, and decide to go on from there.
It might be a very nice item to keep, perhaps hand it down to future generations, or maybe you would like to sell it to a collector or a war museum if they are interested.
