To the popular saying, "Reduce, reuse and recycle," today's conscientious shoppers are adding a fourth "re": Resell. Peer-to-peer and online secondhand sales business are booming, from Facebook Marketplace with its 4 million-plus followers to secondhand clothing marketplace thredUP, which paid out more than $58 million to participating sellers between 2012 and 2017.
Add on Craigslist, Ebay, yard sales, thrift shops and flea markets, and the possibilities for environmentally- and budget-conscious used item purchases are unlimited.
But before you rev up the laptop or pack a bundle of ones to hit the Saturday morning garage sales, take a second to get familiar with secondhand purchases that are a bad idea.
Some of these "don'ts" fall in the "buyer beware" category: There are simply too many costly things that could go wrong and ruin even a minor investment. Other items should be avoided at any price because once they're used, they may involve health or safety issues.
Here is the expert take on 12 things you should never buy secondhand:
Car seats. Unless you know the seller and the seat still has an owner's manual that states its expiration date, protect your kid by purchasing a new car seat.
That's right, car seats have a "shelf life," or a literal expiration date, according to Money & Career Cheat Sheet. "Most expire after six years, a date often printed on the owner's manual (which we doubt you'll get when buying it secondhand),"according to the personal finance blog.
"Plus, technology improves over time. The safest car seat for your child will likely be a recently manufactured one. There's also no way to know if the seat has been involved in an accident, a fact that the seller likely won't tell you if they're trying to pawn their used car seat."
Laptops. Buying just anyone's posted laptop is usually not a good idea, according to the Cheat Sheet experts. "Laptops are portable and therefore subject to the wear and tear that desktops are spared," it explained. "Think back on all the times you've dropped your laptop or left it loose in your bag to bump into all your other electronics. If you buy a used laptop, you usually don't get the warranties and tech support you get buying a new device." This doesn't rule out refurbished laptops, though, since the tech company reselling such electronics has usually inspected them and cleared them for resale and often offers guarantees and returns.
Shoes. That "walk a mile" thing should not be taken literally, according to Reader's Digest. "Used shoes have been molded to their previous owner's feet," it explained. "Poorly fitting shoes can cause pain and health problems over time. Running shoes, in particular, have probably lost most of their absorbent cushioning by the time their first owner is finished with them."
Mattresses. Even with modern-era mattress toppers, cushy comforters, stylish duvets and lots of decorator pillows on top, preowned mattresses can be subject to mold, mites, bed bugs, fleas and various other bacteria over time. "A used mattress can be terrible for your back, too," Cheat Sheet noted. "Even top-quality mattresses are only intended to last eight to 10 years."
Vacuum cleaners. There's usually a reason someone doesn't want a vacuum cleaner anymore. (And the stories about "little old ladies who only vacuumed on Sundays" won't really ring true, either.)
The models that cost more than $1,000 new can still be super-tough to clean, according to CS. "It's unlikely a used vacuum cleaner will ever work as well it once did, and they're also fairly expensive to fix — even pricier than if you just bought a new one to begin with," it added. A better idea: instead of trying to save by purchasing a used vacuum, buy a new but smaller, portable vacuum that's easier to use and clean.
Bike helmets. Each helmet is really only designed to withstand one accident, according to Wise Bread, contributing to "U.S. News and World Report." Unless you personally know a helmet's entire history, it's much safer to buy a new one.
Summer hats. Some of the "save your money" ideas apply even to the lowest-cost secondhand items, and hats are a prime example. "Have you ever figured out how to clean a straw hat? Nope? Then it's a safe bet that the person selling you their old vacation head cover hasn't, either," CS explained. "A used hat may come cheap, but it also probably comes with skin infections, old sweat stains and the remnants of hair gel or, even worse, dead skin."
Most speakers. Smart phones and televisions might receive kid glove treatment, but lots of owners treat their speakers more casually, which can compromise the fairly sensitive technology. "The audio equipment doesn't hold up as well as many think," CS warned. "Think about how the performance might be compromised by how loud the former owner blasted their music. The damage won't be obvious, so use caution if buying a used speaker."
Microphones. This is another often mishandled, sensitive audio item you shouldn't buy used, according to Wise Bread. If the mic has been dropped one too many times, you can't necessarily see the damage but its performance will be compromised.
Wetsuits. If a wetsuit has done anything but sit unused in the closet (and there probably are some of those on the market from over-optimistic hobbyists), don't pick it up even on sale. The constant change in water pressure with scuba diving wears a wetsuit out and will make it very likely to tear after you buy it (if it hasn't already.)
Pet food or treats. Sure, your best friend eats anything. But in the secondhand market, that's not always a good thing, according to "Reader's Digest."
"While buying gently used pet toys or food bowls is probably safe, you'll definitely want to stay away from buying pet food or treats secondhand. They could be expired, recalled or even infested with insects or their eggs."
Cat trees. "Animals can spread fleas and fungal infections just by contact, so you risk bringing those diseases into your home by buying used," CS noted.