If you stockpiled disinfectants last year at the beginning of the pandemic, now’s a great time to check your stash. Just like food, medicine, and cosmetics, cleaning products have a shelf life, and using yours outside of the optimal time frame could result in less effective disinfecting.

How long you can use your disinfecting products ultimately depends on what you’re using. Here’s what you need to know about when to use (and replace) three of the most common categories of disinfectants. (And if you still have store-bought disinfectants from the early days of the pandemic, yours might be expiring right about now.)

Store-bought disinfectants

In general, store-bought disinfecting products have a year-long shelf life, according to Nathan Sell, Director of Regulatory Science at the American Cleaning Institute . “The one year of effectiveness typically begins with the manufacture date,” he says. “The expiration date is there because over time, the active ingredient, or the chemical doing the advertised action, may degrade.”

Unlike a carton of eggs, there’s no actual “best by” date on your Clorox Wipes or Lysol spray. Instead, Sell says, look for the manufacture date. You should be able to find that printed on the product label — Clorox , for example, usually prints theirs on a black stamp on the side near the bottom of their products— or by following a QR code to additional details online. Then, add a year to determine if your disinfectants are still as effective as when you first bought them. If not, then it’s probably time to swap them out for new ones.

DIY bleach solutions

Store-bought disinfectants aren’t the only thing you need to keep tabs on. Elizabeth Scott , PhD, a professor of biology at Simmons University and founder of the Simmons Center for Hygiene in Health in Home and Community, says common DIY solutions degrade even more rapidly.

For example, while it’s important to dilute bleach with water before using it to disinfect, keep in mind bleach is less stable in its diluted form — which means temperature, light, or contamination can cause it to degrade within hours or days. It’s unlikely, Scott says, that the solution would become unsafe to use, but it will probably become less effective the longer it sits. Make a habit of using your DIY-diluted disinfectants right away rather than, say, premixing them and putting them in a spray bottle for long-term use. (That’s also not a good idea because the metal part of the spray bottle can interfere with bleach’s effectiveness.)

Alcohol-based hand sanitizer

It’s probably unlikely you still have hand sanitizer left over from a few years ago, but those expire, too. The alcohol, the active ingredient in most forms of hand sanitizer, evaporates when it’s exposed to the air, which starts happening as soon as the bottle is open. Most hand sanitizer bottles aren’t air-tight, so the effectiveness will dwindle over time, ultimately bottoming out at around three years. Again, your expired sanitizer probably won’t hurt you, but it’s definitely worth replacing if it’s not going to stave off potentially harmful pathogens. When in doubt, opt for hand-washing with soap and water instead — it’s always better to be safe than sorry!