"Vintage" means different things to different people. I'm not so interested in a mid-'70s era Japanese receiver. I'd be very interested in pre-WarII theatre-related loudspeakers and amplifiers/transformer and the like.
What kind of "vintage" are you talking about?
Some equipment is enduring; some is cool for the period, but subject to the limitations at the time. Some probably isn't worth the trouble.
What are you after?