Today’s programmable slow cookers often come with the ability to cook food for up to 24 hours, as well as automatic warming settings that can stay on for just as long. However, the phrase, “Just because you can, doesn’t mean you should,” comes into play here.

When you’re whipping up a meal in a slow cooker, there are a number of (often unspoken) limitations on how long you should leave food in the appliance, both when cooking and keeping it warm.

If you’ve ever gotten stuck at work for a few hours longer than anticipated, you may have come home to mushy vegetables, chalky meat, or a rather bland soup in your slow cooker. While slow cooker recipes are designed to cook for extended periods of time, they can still become overcooked if left on the wrong setting for too long.

In general, it’s best to stick to the indicated cook time on the recipe you’re following. Most slow cooker meals take eight to 12 hours on low or four to six hours on high, but there are also recipes for slow-cooked meat that take up to 24 hours. If you want to avoid overcooking your dish, follow the given guidelines as closely as possible.

Concerned about getting home on time to turn the slow cooker off? While older slow cookers often require you to manually switch between settings, today’s programmable slow cookers include a digital timer that automatically changes the appliance over to the warming setting after the set duration. This way, it will be cooked to perfection—no matter when you end up getting home.

Even fancier models, such as the Hamilton Beach Programmable Temp Tracker Slow Cooker, come with a temperature-tracking probe to insert into the dish. You can then set the slow cooker with the proper cooking temperature, and when it reaches that point, it will either switch to warming or maintain the temperature, depending on your preference. Cool, right?

There’s also the issue of how long you can leave your slow cooker on its warming setting — after all, it’s tempting to leave the appliance on warm during holiday gatherings or other events. Most appliances will automatically shut off after 20 or so hours on this setting, but you shouldn’t leave food in a slow cooker for an extended length of time.

The general rule of thumb is that two to four hours is the maximum length of time you can leave food in a slow cooker on warm. After this, it needs to be transferred into the refrigerator.

Why? Most warming settings keep food at around 145 degrees Fahrenheit, which is extremely close to what the USDA refers to as the “Danger Zone.” Between 40 and 140 degrees Fahrenheit, bacteria grow extremely quickly, doubling in number in as little as 20 minutes. So if you’re opening the lid frequently or the slow cooker isn’t maintaining the temperature precisely, your food may become spoiled if you leave it out for too long.

Besides limiting the time you leave food in the slow cooker, there are a few other ways you can ensure meals are cooked safely and stay fresh for as long as possible.

  • Thaw Meat Before Cooking
    It might be tempting to put a frozen piece of meat into your slow cooker, but when you do this, the meat takes longer to cook and its interior may not reach a safe temperature in standard cooking time.
  • Keep the Lid On
    The University of Minnesota notes that the internal temperature of a slow cooker drops 10 to 15 degrees every time the lid is opened, slowing the cooking process by 30 minutes. So resist the urge to peek!
  • Don’t Overfill the Pot
    You should never put so much food in your slow cooker that it’s more than ⅔ of the way full. Not only can this cause it to overflow, but it can also lead to undercooked food, as it takes longer for the contents to get to temperature.
  • Double Check with a Thermometer
    When in doubt, don’t be afraid to double-check the temperature of your meal using a kitchen thermometer. If it’s not at the recommended temperature, leave the dish to cook for more time.

While slow cookers are known for being a hands-off appliance, it’s important to follow these safety precautions each time you break it out.