There’s really nothing quite like finding an incredible piece of clothing sitting on the rack in a thrift store. Among what seems like millions of grandpa sweaters might be a vintage cashmere lurking, or a pair of Prada heels unassumingly tossed in a pile of Payless flats. When you’ve spent more time than money hunting for them, nice things earn a unique luster.

While thrift shopping may have once been on the to-do list of people in poverty or otherwise on tight budgets, a rise in eco-conscious thinking and the tempting price tags of second-hand goods has caused young people to pop to their nearest charity shops. In 2019, around 40 percent of Gen Z-ers were buying second hand, compared to less than 30 percent in 2016, according to a report by resale service ThredUp. The idea here is that buying previously owned stuff keeps products in circulation for longer, making those vintage mom jeans and slouchy turtlenecks appear fabulous for you and the environment. “It’s definitely becoming much more popular, and that’s because people are looking for sustainable and guilt-free ways to shop,” says Anna Fitzpatrick, a Ph.D. student and project coordinator at the London College of Fashion’s Centre for Sustainable Fashion.

And on the surface, that’s really great.

But what scientists, environmentalists, and urban planners have come to realize over the years is that some trendy sustainable practices could actually be harmful to marginalized people (just look at how plastic straw bans inadvertently made life harder for individuals with certain disabilities). In the case of thrifting—when you take into account price hikes, size-ism, and the promotion of an unhealthy attitude towards clothes and waste—casting it as a perfectly guilt-less and planet-friendly choice is a bit of stretch. Luckily, there are some ways to still snag unique pieces at brag-worthy prices without falling into an ethical black hole.

Reducing the amount of clothing in circulation is essential

Over the last 50 years, the clothing industry has endured a fairly extreme makeover. People used to shop when they changed sizes, jobs, and climates. But with the boom of fast fashion in the 1980s, shopping has become less about necessity and more about rapidly following the trends. Instead of buying one $100 sweater, we can snag a handful of $30 ones that might not last as long.

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The trouble with this is that when you can make clothes at rock-bottom prices, they become more or less worthless. In 2018, the world produced more than 17 million tons of textiles, according to the Environmental Protection Agency—compared to only around 2 million 50 years ago. Out of that massive pile, 11.3 million tons entered the landfill.

Even before clothing reaches the racks, 35 percent of the materials used to create those garments—be it fabric cut off during creation or waste product that ends up getting incinerated—ends up as trash, according to a report by fashion industry business network Common Objective. Every one of those products, wherever it ends up, uses resources like the thousands of gallons of water it takes to make a single pair of jeans.

“Keeping garments in circulation longer, and all of the natural elements embedded in those garments out there for longer, is the best thing we can do,” says Lynda Grose, a sustainable fashion expert at the California College of the Arts. Wearing a blouse or suit as many times as possible gets the most bang for its environmental buck.

“It makes sense to have those garments looped around a second, third, fourth, or fifth owner with the idea of slowing that extraction down,” Grose continues. “We’ve got to slow or halt the extraction.”

The most powerful thrift shopping can be done in your own closet

The root of a lot of sustainability dilemmas is not only assessing what you use in your life, but the excess in it as well. Fashion lovers might think that swapping out their Zara hauls for piles of Salvation Army clothing is helping to build a sustainable future—but it’s not. “It doesn’t challenge our addiction to shopping or the idea that we can have new clothes whenever we want them,” Fitzpatrick says. “It enables it.”

In some cases, the very existence of thrift stores can give us a false sense of guiltlessness, Fitzpatrick says: We can swap out our entire wardrobe by dumping what we don’t want at a second-hand store with the hopes that it’ll be put to good use. Instead of buying less, we trick ourselves into thinking we can shop our way out of the problem by donating again and again.

The other reason thrift stores are so well-stocked these days is because of quickly we cycle through trends. ”[Thrifting] feeds off the instability and unsustainability of the fast-fashion industry,” Fitzpatrick says. “Without that, there wouldn’t be such a massive second-hand market.”

In fact, the volume of clothes is so high, only a small slice ends up in thrift stores. Out of the bag of donations you drop off at Goodwill, only around 10 to 20 percent will be displayed under the fluorescent lights. The remaining 80 percent is shipped to other countries like Poland, Pakistan, and Kenya or turned into rags or post-consumer fiber. Recycling textiles, however, is an energy-intensive task.

Shipping unsold clothes presents yet another conundrum. Dependence on the West’s waste diverts attention to building up local economies, Andrew Brooks, a development geography lecturer at King’s College London, writes in an article in The Guardian.

“Once fragile economies were open to imports–like, second-hand clothes, there was a wholesale collapse of vast swathes of local industry,” Brooks writes. “Cheaper imported goods flooded African markets and workers in clothing factories lost their jobs.” Some countries have even started banning imports of thrifted garments.

One of the most radical ways to fight these systems is to shop your own closet first and take on the burden of mending or upcycling pieces you have or haven’t worn before stepping foot in a store, says ethical fashion expert de Castro. “You will probably find that there are multiple pieces that you can customize or chop or swap, restyle, and re-wear,” she notes.

Of course, that won’t bring the same thrill as digging through a pile of used sweaters to find the one you were destined to don. “I would never deny that joy to anyone,” de Castro adds. But the key is to start with the things you already own, so you can avoid dumping loads of donations at the local charity store.

The social ethics of thrifting aren’t so cut-and-dry, either

While shopping second-hand may seem like a fun, or even adventurous, activity, it’s absolutely crucial to remember that, it has been and still is, essential for people of limited means.

As thrifting reaching new levels of popularity, troves of people are noticing a rise in prices at their local thrift stores. This can take a serious toll on the folks who rely on the used market for everyday wear. “They aren’t shopping in second-hand shops to be aspirational or sustainable or cool—they’re doing it out of necessity,” says sustainable fashion student Fitzpatrick. “That’s something that’s not talked about often.”

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The impacts of rising prices on the online resale world are markedly clear. As culture and fashion magazine Dazed pointed out over the summer, a pretty ordinary sweatshirt that might go for less than $5 at a Goodwill can be marked up anywhere from four times to 700 times that price online. “We now risk making people who buy cheap clothing be ashamed of their income,” says Orsola de Castro, founder of Fashion Revolution, an international enterprise focused on sustainable and ethical fashion.

So, when you walk into a thrift shop or really any store, it’s important to ask yourself why you want the product, if you truly need it, and also who else uses the shop, Fitzpatrick says. There’s also a big difference between Salvation Army and vintage boutiques, she says. If you love period pieces and can handle a higher price, maybe turn to a more curated consignment shop instead of buying up the more affordable options.

Secondly, the fashion industry hasn’t always been kind to buyers who wear larger sizes. Many brands don’t cater to the average American person, which for women is a size 16-18. According to Vogue Business, while 70 percent of American women wear a size 14 or larger, a mere 20 percent of clothing is made in those sizes. As fashion icon Tim Gunn told The Washington Post, that can make shopping a “horribly insulting and demoralizing experience.” And because thrifting is literally just putting clothes that designers have made back in the cycle, the pool of clothing that fits the average person can be tiny, even at the most well-stocked thrift stores.

“Only certain people can participate as sustainable consumers,” says Fitzpatrick. Additionally, trimmer shoppers can take a garment and have it fitted to their size in a way that larger people simply can’t. A size 8 dress can be tailored to fit a size 4, but it’s a much more challenging affair to turn a size 4 dress into a size 18.

Where buying second-hand used to be economical and sustainable, it’s now about consumption and staying on trend. “Thrifting has become very niche,” de Castro says. “It’s an initiative of the people who have the time and money to do it.” Just remember, when it comes to your closet, less is more helpful for society and the planet.