I don't necessarily consider the "age" of items in my fabric stash when choosing what fabric to use in a particular project. If it fits the color range needed and in general is an ok fabric for the usage it doesn't matter to me if its older than I am or brand new. In fact most of my stash is anywhere from five to ten years old and quite a bit is older than that. And I consider all of it fair game unless it is designated for a particular project.
I am currently collecting fabrics for two vintage projects, a double wedding ring and a grandmothers flower garden variation, for which I want all the fabrics to be reminiscent of the fabrics in the ones I had once upon a time. So those will definitely not be using new fabrics. Will most likely use some that are probably really 70s/80s just because they look right with the older ones.
And then there are batiks! Are they retro or modern or timeless?