Not all iPhones are the same. These cost less and are better for the earth.

Gadget-shoppers, take a lesson from the fashionistas: “Previously loved” iPhones are in vogue.

I know “refurbished electronics” sound about as sexy as hand-me-down Crocs. But smart fashion hounds seek out good deals at consignment stores. And in the era of $1,000 – or, even, $2,000 – smartphones, used gadgets are having a renaissance, too. It’s good for both your wallet and for the earth.

And I bet you couldn’t even tell the difference.

Hidden behind the hoopla Silicon Valley generates about the latest-and-greatest, there’s a giant economy of reused phones. Apple, Samsung, phone carriers and retailers are offering big trade-in deals for older models. Then they spiff up the used stuff, often with fresh batteries and exteriors, and sell it for 15 to 40 percent off – if you know where to look.

One in five phones sold to Americans in 2018 were used, and it’s a growing share of the market at a time we’re buying far fewer phones, according to Counterpoint Research.

A third of that is officially refurbished gear, sometimes called certified pre-owned or CPO. It’s just like the real thing, because it is the real thing, often including the standard one-year warranty. (These are also the devices companies give out as warranty replacements.) The tricky part is, you have to buy from a reliable source.

To figure out how to do it right, I went on a shopping spree. I bought a bunch of likenew iPhone 7 Pluses with 32 gigabytes of storage, $569 new, from Apple’s “certified refurbished” online store, from eBay, from Amazon and from refurbished store Back Market. The products all arrived in great shape, but with wildly different warranties, packaging – and prices. There are now places to find used gear that check it’s not stolen, and don’t make it feel like you’re buying out of the back of a creepy van down by the river. (Amazon CEO Jeff Bezos owns The Washington Post.)

No, refurbished electronics aren’t for anyone who has ants in his pants about owning the absolute latest. But you can already find last fall’s iPhone XS on some sites, and there are great deals for laptops and tablets, too, from companies including Microsoft and Dell.

If saving money isn’t enough motivation to go refurbished, you could also pat yourself on the back for helping the planet. Seriously: Don’t hug a tree, buy a used iPhone. The energy that went into manufacturing smartphones for the last decade exceeds all of India’s annual electricity use, according to Greenpeace. Making new phones also requires vast quantities of water and conflict minerals.

Tech companies could help the problem by designing devices to be more easily repaired and recycled. For consumers, the best way to stem the environmental damage is to buy less new stuff.

One reason there’s a thriving refurbished market is that tech companies are making devices that run the latest software longer. On phones, Apple does this best: Its iOS 12 runs on the iPhone 5S from 2013. (Samsung’s latest update only supports phones back to the Galaxy S8 from 2017.)

And for many people, the latest hardware options just aren’t that appealing, with rising prices and ho-hum new features. I’m a tech columnist, and even I am still happy with a 2012 MacBook Pro I use for everyday work. (Buying used are among the few ways to get Mac laptops with older-style keyboards, or an iPhone SE, the last “small” phone Apple made.)

What everyone fears is getting a dud. In my shopping experiment, in which I focused only on the “mint” or “pristine” iPhones, everything arrived in such good condition that I couldn’t tell them apart. But I learned a few important questions any defensive shopper should ask: What is the warranty? What state is the battery in? And what’s the reputation of the people you’re buying from? These are especially important if you’re buying from an anything-goes marketplace like Craigslist, where I also recommend asking sellers for a product serial number. (Before you buy, you can look up serial numbers on sites such as Apple’s check-coverage tool to see if it is still covered, or even stolen.)

So which store is best – and worst? Like all deal hunting, it depends on how much work you’re willing to put into it, but also if you’re willing to risk a shorter warranty. Here’s what I learned shopping for a like-new iPhone 7 Plus.

Apple Certified Refurbished Amount I saved: 16 percent, $479 Warranty: 1 year, provided and serviced by Apple, on everything

Likes: It’s a no-brainer to make the company stores from Apple, Samsung, Microsoft and Dell your default place to start shopping. Apple, for example, not only tests and cleans everything it sells but also throws a new battery and outer shell into every refurbished iPhone and iPad. Products ship in a new box you’d feel great about gifting. And best of all, the stuff in the store comes with the exact same warranty as new items - a year of service.

Dislikes: The company stores are likely to save you the least money. And items can flow in and out of stock erratically.

Back Market Amount I saved: 18 percent on an Apple-certified model, $469 plus shipping

Warranty: 1 year, provided and serviced by Apple, on my deal (but 6 months for other merchants)

Likes: With backing from Bernard Arnault, chairman and chief executive officer of LVMH, the world’s largest luxury goods company, Back Market makes buying refurbished easier by removing some of the risk and guesswork you’ll find on other marketplaces. It grades products for quality ranging from “Shiny” to “Stallone,” and includes standard minimum 6-month warranties on all products. And it is the only U.S. marketplace that sells Apple-certified gear, including the same Apple warranty as buying direct.

Dislikes: Back Market was the slowest to ship me the used iPhone, and also has a limited selection of certified Apple products. Its selection of gear refurbished and guaranteed by third parties is decent, but savings aren’t as great as some competitors.