Many things have a best before date, and that does not mean 'if it hasn't expired, don't throw it away.'
- Large Cooking Oil Bottles
The shelf life of cooking oil is typically between 12 to 18 months, but this only applies when the bottle is unopened.
A study found that after opening a 1-liter bottle of sunflower oil and using it for a month, the peroxide value increased from 2.98 to 18.08, approaching the threshold (values above 20 are not safe for consumption, measured in meq/kg).
When the oil goes bad, peroxides, aldehydes, and ketones can form, which may lead to nausea and vomiting, and prolonged consumption can strain the liver.
For oils that we use almost daily, we should: Keep the oil bottle away from light and high temperatures like those in the kitchen; Use opaque bottles to store the oil and clean them thoroughly when refilling; If the oil turns darker or starts to smell, discard it immediately; If usage is slow, it’s better to buy smaller bottles.
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Wooden and Bamboo Products
Wood and bamboo utensils (such as cutting boards and wooden chopsticks) that have been in use for several years can become a breeding ground for bacteria.
After two years of use, the total number of colonies, molds, and coliform bacteria increases significantly, with colony counts often exceeding 3,000 per square centimeter (cfu/cm²).
Using these worn-out cutting boards to chop fruits or prepare cooked foods can lead to foodborne illnesses, such as diarrhea and stomach pains.
I recommend checking your cutting boards and chopsticks today: If there are deep scratches, cracks, or visible mold, dispose of them immediately; Even without these issues, it’s best to replace them after two years of use.

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Non-stick Pans / Rice Cookers
The coatings of these items are often made from Teflon (polytetrafluoroethylene), which is safe and non-toxic as long as it remains intact.
However, once the coating wears off and flakes, harmful substances such as acrylamide can be released when cooking at high temperatures.
If the following occurs, you should replace the appliance: The coating is visibly flaking with large scratches; Rice begins to stick and burn at the bottom; The appliance has been in use for over 5 years.
Many people continue using dish sponges until they are visibly worn out.
What most don’t realize is that every gram of a used dish sponge can release 6.5 million microplastic fibers, essentially “spreading plastic” each time you wash dishes.
For dish sponges, they should be replaced in the following cases: Mold or smell; When they feel stiff or crumble; After being used for over a month, with a maximum of 2 months.
Some people may look pristine and stylish, but their underwear can be embarrassingly worn out!
A study found that a pair of underwear worn for just one day contains an average of 0.1 grams of fecal matter.
If this matter is not thoroughly washed or replaced in time (sometimes it cannot be fully cleaned), the residue can lead to urinary tract infections, prostatitis, and other issues.
Signs that it’s time to replace your underwear: Distortion, the fabric becomes thinner and more transparent; Yellow stains and stiffness; Worn for 3 to 6 months.