I might be a lover of all things from the 1970's, but that doesn't mean that I sling polyester and vinyl around my body without a second thought. Sure, I'll be the first one to rush to the Salvation Army on half off day and buy up clothing from decades past—including pieces made with non-biodegradable materials—but you'd better believe I'm choosey about them. And when I'm finally through wearing those clothes, I give them straight back to the thrift store market. Why? Because fabrics like polyester and vinyl will live much longer than I will—much, much longer. And if I don't dispose of them properly, they'll sustain that life while in a landfill.
It's simple. It's all about choosing the right fabrics and disposing of the wrong fabrics the right way. The 'right' fabrics are the ones that are biodegradable and sustainable. Clothing made from materials like organic cotton, hemp, and bamboo will, eventually, decompose—even if stuck in a nasty landfill. Clothes made from synthetic fibers won't. They'll stick around forever as evidence to future generations that you didn't think twice about throwing away your garments. Not cool.
So the first step to dressing responsibly is picking the right fabrics. The second step is disposing of your fabrics properly. Even if you pick the right fabrics, don't throw them away when you're through with them. There are still people out there, I guarantee, who can find a use for your clothing when you're done with it. But if you buy the right fabrics to begin with, at least you'll know that when your purchase does, inevitably, end up in a landfill, it won't be there forever.