## Running sneakers When deciding on the need to buy new athletic sneakers, we usually focus on the fact that the old pair of sneakers is worn out or looks run down. However, studies show that they lose their shock-absorbing properties after about 300 miles of wearing sneakers. This creates an excessive load on the joints, which can lead to serious injuries. Unfortunately, sneakers do not have a speedometer, so you should calculate the mileage yourself and change your running shoes regularly. ## Household chemicals The chemical compounds in our products to clean our homes degrade over time, becoming ===less effective or toxic. Additionally, their fumes can become more corrosive after expiration, causing dizziness, nausea, or respiratory irritation. ## Batteries and rechargeable batteries The expiration date of batteries matters, even if they are not in use. Old batteries can leak, releasing harmful chemicals to the skin and respiratory system. The risk is especially high if stored in inappropriate conditions, such as high humidity or extreme temperatures. In addition, releasing toxic components such as cadmium, mercury, or lead into the environment can contaminate soil and water, posing a risk to humans and the ecosystem. ## Medical accessories Using expired medical supplies such as thermometers, glucometer test strips or patches is ineffective and dangerous as the chemical elements can decompose and become toxic. ## Hydrogen peroxide Hydrogen peroxide is a mandatory component of even the simplest first aid kit. Most people open a new bottle and then reuse it every time it is needed. However, the issue is that after being opened, a bottle of hydrogen peroxide retains its medical properties for no longer than two months, turning into ordinary water. While it does not cause harm, it becomes ineffective regarding the intended purpose. ## Toothbrushes The shelf life of a toothbrush is usually about three months from the date you begin using it. Over time, the bristles lose their shape and become stiff or too soft. This reduces their effectiveness in removing plaque and dirt. The humid bathroom environment promotes the growth of germs, which increases the risk of gum inflammation, tooth decay, and oral infections. > If you have an infectious disease (such as a cold, sore throat, or flu), it's best to replace your toothbrush right away to avoid re-infection. ## Hairbrushes and straighteners The older styling devices get, the more their heating and protective elements, particularly the ceramic coating, degrade. This can cause irreparable damage to your hair. And remember that old electrical appliances tend to catch fire, which can lead to a house fire. ## Creams and lotions Generally, skin creams and lotions have two expiration dates on the container. One is for storage in sealed form, and the other is for how long it is good after the first time it is opened, which is a shorter expiration date. After the expiration date, the chemical composition can change, increasing the risk of allergic reactions, skin irritation, and even dermatitis. ## Mascara and eye shadow Old cosmetics can be a source of bacterial growth. Using such cosmetics increases the risk of eye infections. > The same guideline applies here as with creams and lotions: once mascara or eye shadow is opened, their expiration "clock" starts ticking faster. ## Bras This undergarment has no stated lifespan but loses its functional properties–even if it still looks good. Over time, the elastic materials stretch over time, and the frame loses shape. This reduces the level of breast support and leads to discomfort, including back, neck, and shoulder pain. This is especially true for women with larger breast sizes. In addition, old fabrics can accumulate sweat, sebum, dead skin cells, and microbes, which can cause irritations and allergic reactions. Depending on the frequency of use, bras should be replaced every 6-12 months.