I was lucky enough to have a few house records published in the 80's and 90's. An initial run of a record would always include a few hand-labeled "test pressings" that we would take around to radio and club dj's to see how they would fare in the mix - and also to build the buzz.

It was always a rush, going to a full club or hot radio station and handing "fresh wax" to the dj - no it was not really wax - and getting immediate feedback. Very similar to launching a new app or feature these days!