7 Household Items You Should Never Buy Used

From used music CDs, to online consignment stores for both adults and babies, to supporting fashion designers who remix thrift store finds, TreeHugger is a big fan of buying used, because it cuts down on unnecessary waste by promoting re-use and creative upcycling.

While reusing things is an eco-friendly idea and will undoubtedly help you save money in the long run, there are still some things one should avoid buying secondhand in order to ensure your health and safety and that of your loved ones. Here are some items that you should never buy used:

1. Mattresses, box springs & upholstered furniture

Thanks to a recent resurgence in bed bugs in urban areas, mattresses and upholstered pieces of furniture that you find curbside or in thrift stores could be potential havens for these famously tenacious and relatively long-lived critters, whose bites may even pass on super-germs. Plus, there's the yuck factor behind the millions of dust mites and pet dander that are embedded in an old mattress.Now, for habitual furniture restorers, we know it's hard to pass up on that antique chair, but it may save you thousands of dollars in bed bug extermination costs and hassle. If you do choose to take that risk, make sure you inspect carefully, clean it well and re-upholster it completely as a precaution.

2. Baby cribs

There's no doubt that buying secondhand baby items like clothes, toys and furniture will help parents save a ton of money in the long run, especially since kids outgrow their stuff so darn fast. However, steer clear of buying used baby cribs -- nearly 10 million were recalled during 2007 to 2011 in the United States alone, due to tightened safety regulations, which enforced stricter testing and prohibited the sale of potentially fatal drop-side cribs. If you must buy a used crib, check that it hasn't been recalled.

3. Car seats

Car seats are another one of those expensive baby goods that may initially seem all right to use secondhand, however, but it may endanger your child. Since safety regulations do change from time to time, you may be unknowingly using one that is not up to current standards, or may have been recalled or have missing parts. Also, a used car seat may have been involved in a prior accident, weakening its integrity, even though the damage is not visible. If it's something you really cannot buy new, ensure that you have the original manufacturer's installation instructions to put it in the car properly, and check that it has not been part of a recall.

4. Helmets

Like car seats, the same rationale goes for used helmets. It may look like it's in good condition, but it's not always apparent if it sustained unseen structural damage in a previous accident. Since it's a critical piece of protection for your head, it's better to buy new and intact, than to take a risk.

5. Swimwear & underwear

It seems obvious, but swimwear and underwear should be bought new, unless you like having other strangers' unknown germs, old bodily fluids and god-knows-what-else right next to your intimate parts.

6. Cosmetics

Here is yet another common sense no-no: do not buy or use other people's old cosmetics. Not only could you potentially get infected with yummy things like oral herpes (cold sores) and conjunctivitis (pinkeye), you could be using expired stuff that probably isn't too good for your skin. Better to find fresh, new cosmetics that follow a green standard -- or even better, make your own with easy ingredients that you might already have in the house (we've got recipes for sunscreen, body scrubs and body butter). Or forego them altogether -- there's enough hypocrisy and greenwashing going on in the cosmetics industry that might already have you skipping the mascara.

7. Tires

All right, tires aren't really a household item, but over 30 million used tires are sold in the U.S. each year, so they are quite common to a lot of households and their cars. However, many consumers are taking a risk; used tires could have poor traction due to insufficient tread depth, or cracking due to dry rot, or have invisible, internal damage from being in an accident. Old tires could be recycled in other ways, be it for building earthships and sheds, or making flooring or chic bags, or evil mutant sculptures with them.

Now, there are probably other items that we could buy used but that could be all up for debate -- after all, we know that there's a huge environmental cost in dumping our electronics rather than reselling or recycling them, but buying secondhand gadgets is always a bit of a gamble, especially if unknown repair costs could outstrip the original purchase price. But as a general rule, and with a few exceptions, it's often more environmentally friendly, cost-effective and more fun to buy used.

What do you think: are there other items that you would never buy used and why? Let us know in the comments below.