Know your brands and remember that big names like Givenchy license their name for low quality mass-market garments. Avoid synthetics in vintage clothing and just skip anything made in the third world. With few exceptions, there’s no reason to buy used clothing that was made to be low cost. Speaking of cost, use your smartphone to check prices on eBay before you invest. And double-check tricky labels, there’s a world of difference between Brioni and Baroni. Happy hunting!