Household items like brushes and pillows don’t go out of style as quickly as say, your handbag or cell phone, but that doesn’t mean they should linger season after season. Dirt, germs and general use on items we use every day means that they require upkeep—and eventually, replacement. Sara Snow, green living expert and author of “Sara Snow’s Fresh Living” explains the freshness factor of our everyday essentials.

Mattresses

Your mattress may have a lifetime guarantee, but that doesn’t mean you should keep it longer than a decade—especially if you’re an allergy sufferer. “Mattresses can become a hot spring of dust mites and they can lose their form and ability to properly support your body, generally after seven to ten years of use,” says Snow. If you get a better night’s sleep on your friend’s pull-out couch, it’s probably time to part ways with your current mattress. Snow recommends purchasing an eco-friendly model made from natural materials such as organic wool, organic cotton and latex.

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Pillows

Proper care can keep a good pillow going for years. “So as long as you’re washing your pillow cases and zippered pillow protectors these should last at least a few years,” says Snow. Martha Stewart recommends fluffing your pillow every morning to extend its life, but remember that inner materials such as down feathers, cotton and foam break down and lose their ability to support your head and neck, so there comes a time when even the best-tended pillows must be pitched. When it’s flat and won’t hold its fluff, you’ll know it’s time.

Running sneakers

You’ve covered miles in these shoes but if that distance tallies up to 400 miles or more, it’s time to shop for a new pair. Changing out your sneakers helps prevent injury to joints, muscles and bones—the result of pavement pounding and wear-and-tear on the structure of your shoes. Most non-marathon runners should swap out their pair annually, says Snow. If you run the equivalent of 3–4 miles, three to four times a week, then do it out sooner; closer to every six to nine months.

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Air filters

You’ll breathe easier—and cleaner—if you keep tabs on the air filters in your home heating and cooling system. Snow recommends choosing a high-efficiency air filter, which pulls more dust and debris from the air, but that also means they dirty faster, so be prepared to change them often. “Look for a high efficiency filter or one with a high MERV rating (Minimum Efficiency Reporting Value) and change it every one to three months if you live in a warm-weather or dusty climate, and every six months in the winter.”

Sponges

“Sponges (especially those of the kitchen variety) collect all sorts of bad gunk from salmonella to E. coli,” says Snow.  Replace them every few months and make sure to soak them for a good five minutes in distilled white vinegar from time to time (yes, even the ‘antimicrobial ‘ones)—a disinfecting trick that kills 99.6 percent of bacteria, according to Good Housekeeping.

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Hair brushes

“When it comes to hair brushes, forget about how the handle looks and pay attention to the bristles,” Snow recommends. Bristles still intact? Use a comb to remove hair, then swish it around in a sink filled with hot water and a few drops of shampoo, rinse, air dry and reuse, says Snow. But once bristles starting showing some wear, it’s time to replace the entire brush, as damaged bristles can damage hair.

Shower curtains

If you’re still using a plastic or vinyl shower curtain Snow recommends replacing it immediately as hot water can cause the release of endocrine-disrupting off-gas chemicals triggered by the shower’s heat. A safer and more economical pick is a cloth shower curtain (yep, it really does repel water), that can be cleaned in the washing machine whenever it needs refreshing.

Water filters

The manufacturer’s directions on your water filter specify its average life, but you should account for your water quality, consumption habits when deciding if the  filter should be changed more frequently. Consider that filtration quality diminishes over time. Also watch your water for a change in odor, clarity, taste or a decrease in overall pressure—all of which indicate that it’s time for a replacement, says Snow.

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rReusable bags

Reusable bags made from sturdy materials such as cotton can last for years when well cared for. Wash them every few weeks to banish germs and odors left by dirty groceries, meats and produce. If your bags are on a frame and won’t fit in the washer, Snow recommends misting them with a mix of vinegar and water to keep them sanitary.