As fast fashion begins to fall out of favour due to mounting ethical and environmental concerns, the market for second-hand clothing is surging. But how exactly can buying pre-loved apparel help people live more sustainably? And what other factors are fuelling the resale segment?

Luxury retail brand Farfetch has acquired high-end sneaker and streetwear marketplace, Stadium Goods. FarFetch's buyout signals how the luxury fashion world now converges with streetwear's, and how luxe shoppers in particular, expect hunting down rare or exclusive items to be far easier.

Rebag, an online resale marketplace for luxury handbags, is getting additional capital as it prepares to expand its offline retail operations. Across the globe, luxury shoppers are beginning to move away from the status-symbol 'buy-it-new' mentality, as they shop the look by any means possible.

The resale market for streetwear has expanded from niche online communities to form a sizeable part of the $18 billion apparel resale industry. But who are the key players in this world? And what drives people to spend small fortunes to secure particular sneakers, t-shirts and hoodies?