Firstly, the quality of vintage shoes is really bad. They didn't have the same restriction on what went in the heel, so when you try them on now you feel really unstable. It's the one item I avoid. Secondly, if you love it, get it. The arm might be a bit tight or the bust too loose, but taking your piece to be altered extends the life and means it's tailored perfectly for you, so it will last forever. Never buy anything with underarm stains! It never comes out, so I avoid that like the plague. Iron everything inside out to avoid burn marks. And in the '70s they put packets in clothes to avoid moth damage. Unfortunately the packets let off this horrific smell which you can never remove – it's not that musty vintage smell, it's much, much worse...