We’ve all got that one trusty piece of Tupperware that’s been through it all—but how do you know when it’s time to let go? While plastic containers might seem indestructible, they don’t last forever. From cracks to funky lingering smells, there are a few telltale signs that it’s time to swap out your old food storage for something fresher.

Here’s how to tell when it’s time to upgrade your Tupperware stash, according to food safety expert Darin Detwiler.

When is the best time to replace Tupperware?

Even though plastic food containers can last for eons, it’s a good idea to replace them regularly. Probably way more often than you think. In fact, they really belong in the recycle bin as soon as they show any signs of wear and tear.

It’s time to toss your Tupperware when you notice the following:

Stains: Stains can indicate that the plastic has absorbed food particles, which may harbor bacteria even after washing, Detwiler says. “It can also mean the plastic is degrading, increasing the risk of chemicals leaching into food.”

Scratches, cracks, or rough surfaces: Food particles and bacteria can get trapped in these nooks and crannies, Detwiler says. Plus, these spots are super hard to clean, letting bacteria stick around even after washing. “This issue is particularly common if the plastic has become worn over time or if it has been repeatedly exposed to heat, such as in the microwave or dishwasher,” he says.

Warped spots: “If your Tupperware is warped from being microwaved or put in the dishwasher too often, it’s time to toss it,” Detwiler says. “Warping weakens the plastic, making it more likely to leach chemicals or develop cracks where bacteria can hide.”

Is there a general time frame for replacing Tupperware?

There isn’t a strict expiration date for Tupperware, but a good rule of thumb is to replace it every couple of years, especially if it’s used frequently, Detwiler says. “This timeline can vary depending on the type of plastic, how often it’s exposed to heat, and how well it’s been maintained.”

However, if your plastic containers are cracked, smell funky, or discolored, it’s time to toss them, no matter how old they are, he adds.

What about takeout containers?

If you have a stockpile of plastic food containers from your favorite takeout joints, you should probably throw them in the trash ASAP. “While these containers may resemble reusable Tupperware, they aren’t designed for long-term use,” Detwiler says.

For one thing, most disposable plastic containers are made from polystyrene or other plastics, and they can’t withstand the high heat of a microwave or dishwasher. “Reheating or washing these containers at high temperatures increases the risk of chemical leaching (like phthalates or BPA) into food,” Detwiler says.

They’re also not designed for freezer use. If exposed to low temperatures, they may become brittle and crack, potentially exposing your food to freezer burns or contamination.

Thin or flimsy containers can develop cracks and scratches more easily. “These areas can trap food particles and bacteria, making it harder to clean the container effectively, which may pose a risk of contamination over time,” Detwiler says.

Are there health risks to using old Tupperware?

Using old, beat-up Tupperware could be doing more harm than you think. Here’s what health risks you could be dealing with if you hold onto your containers for too long:

Microplastics: As plastic ages, it can potentially break down and release microplastics into your food, especially when heated. While microplastic research is still ongoing, the potential long-term health risks are raising concerns.

Chemical leaching: “Old or damaged plastic can leach harmful chemicals, like BPA or phthalates, into your food,” Detwiler says. “Even BPA-free plastics may leach other chemicals when exposed to high heat over time.”

Bacterial contamination: Cracks, scratches, or rough surfaces on old containers can harbor bacteria and serve as a breeding ground for foodborne pathogens that “can multiply to dangerous levels,” Detwiler says. While most cases of foodborne illness resolve within a few days, some can lead to serious complications, particularly in vulnerable populations like the elderly, pregnant women, and those with weakened immune systems.

Food safety tips for Tupperware use

Taking a few simple precautions can extend food containers’ lifespan:

Clean it properly: Wash Tupperware thoroughly with hot, soapy water after each use, being “especially vigilant with lids, seals, and crevices where bacteria can hide,” Detwiler says. Before storing, dry it completely. “If Tupperware is not dried properly after washing, the residual moisture can create a favorable environment for bacteria to grow,” he says.

Choose the top rack. “Most modern Tupperware is labeled dishwasher-safe. However, it’s best to place plastic containers on the top rack, as the heat from the lower rack can cause warping, especially over time,” Detwiler says. To be safe, always “check the Tupperware for any manufacturer guidelines about dishwasher use,” he adds.

Avoid storing acidic foods for long periods. “Acidic foods (like tomato sauce or vinegar-based dishes) can degrade plastic over time, which may lead to chemical leaching,” Detwiler says. “Consider using glass containers for these types of foods.”

What’s the best type of container to store food?

Tupperware is affordable and convenient, but it’s not your only choice for storing food. Consider these other container options:

Glass containers: Glass is a top choice for food storage because it’s non-porous, meaning it won’t absorb food particles, odors, or stains, Detwiler says. “Glass is also microwave-safe, dishwasher-safe, and doesn’t leach chemicals, even when exposed to high heat.”

Stainless steel: Stainless steel containers are durable, chemical-free, and ideal for dry or room-temperature foods, Detwiler says. “They’re not great for microwaving but work well for long-term storage.”

Silicone containers: Food-grade silicone is another safe option for food storage, Detwiler says. “It’s flexible, lightweight, and heat-resistant, making it a good choice for both storage and cooking.”

The bottom line

Check your  food containers regularly for cracks, stains, or smells, and replace them when needed to avoid contamination and harmful chemicals. If you’re microwaving food often, switch to glass or silicone for safer heating. Plus, choosing reusable, non-plastic options might be better for your health—and the environment.