6 things you didn't know had expiration dates

Expiration dates on food are something most of us understand. Okay, not quite—plenty of us are confused, and that confusion contributes to food waste. Generally, though, we know that food is going to taste better if we eat it before the expiration date, and that long past those dates food might be unsafe.

What most people don't know, though, is that all sorts of other products have expiration dates. Sunscreen, car seats, and even condoms all go bad eventually. Here are a few things you possibly didn't know expired, complete with links to reputable sources where you can read more.

Sunscreen

Sunscreen goes bad over time. This is one I can attest to personally: I used some five-year-old sunscreen and burned really, really badly. Most bottles will have an expiration date and I implore you to take it seriously. According to the FDA, if there's no expiration date, the sunscreen "should be considered expired three years after purchase."

Sunscreen can go back even faster depending on how you store it. According to the Mayo Clinic, you should make sure not to leave your sunscreen outside "in hot weather or in direct sunlight," which might be challenging given the contexts in which people typically use sunscreen. They recommend leaving your sunscreen in the shade, when possible, or wrapping it up in a towel or in your cooler at the beach or picnic.

Car seats

The materials in a car seat wear down over time, which can make them less effective. The seats are only tested to last an expected lifespan, typically around eight years. This is something to keep in mind if you acquire a used car seat or intend to pass a car seat down from an older sibling to younger child.

The National Highway Traffic Safety Administration, the main US government agency that regulates car seats, offers a used car seat checklist for any not-new car seat. Some of this is obvious: You shouldn't use a car seat that went through a moderate or severe crash, as the stress of such events means they can't be relied on anymore. But a few other things are perhaps less intuitive. The agency says you should only use a car seat if you know the model number and manufacture date, in part so you can determine whether the seat is too old. This information is generally included on a sticker on the seat.

The companies that manufacture car seats also generally outline a lifespan for the seats. Graco, for example, says this is usually between 7 and 10 years, but you can find the lifespan for your specific car seat model by checking the manual. If you don't have the manual, you can usually get a copy by contacting the manufacturer, or by checking the company’s website.

Bike helmets

Bike helmets, much like car seats, wear down over time. The exact time varies—the specific time should be in the manual that came with your helmet. If you don't have that on hand, there are some general guidelines to follow. According to Consumer Reports, "many bike helmet manufacturers recommend replacing your helmet every three to five years" and the Consumer Product Safety Commission says that "it may be prudent to replace your helmet within 5-10 years or purchase."

That's a wide range, granted, but every manufacturer and agency agrees on one thing: You should replace any helmet worn during a crash or if that helmet has any visible cracks.

Smoke detectors

Most people don't give their smoke detectors a second thought until they burn dinner, but those devices don't last forever. The compounds these devices use to detect smoke diminish over time, making them less effective over time. The National Fire Protection Association recommends that you replace your smoke alarm every ten years.  So does the American Red Cross. And don’t forget to change the batteries every six months.

Drugs

It's easy to put pills in your medicine cabinet and not think about them until you have a headache, fever, or another ailment requiring relief. But drugs lose their potency over time, which can make them unsafe. According to the FDA, a degraded drug "might not provide the patient with the intended benefit because it has a lower strength than intended." In some cases the breakdown might create toxic compounds with "unintended side effects."

Condoms

The material condoms are made from break down over time. I don't feel like I need to explain much why this is worrying. According to the Cleveland Clinic "an older condom is more likely to tear during sex", which defeats the point of using a condom.