You can’t quite remember when you cracked that pasta sauce. And those chicken breasts look a little funky … but still smell fine. Good, good?

You probably go through this little song and dance every time you open your refrigerator. But experts say pasta sauces can be tricky, the smell test is highly fallible, and most people tend to over-estimate the amount of time their stored stuff will last in the fridge.

Here, a guide to assessing the safety of your refrigerated leftovers based on food storage resources from the CDC, USDA, and Cleveland Clinic.

If you hit the grocery store on Monday and pack your fridge with meat for the week, you’re asking for trouble. Uncooked, unfrozen ground beef, poultry, and fish are safe for just two days. After that, you’re rolling the dice. Also, to dispel two common myths, cooking or microwaving your questionable items won’t kill the germs that may have infested them. If you freeze them promptly, they can stay in there for up to four months.

Unlike ground beef and poultry, you can hold off on cooking whole cuts of these meats for up to five days. That’s because of the density of the meat, which prevents bacteria from making their way beyond the surface of your cuts. These meats will also keep longer in the freezer—up to 6 months.

The smell test is bogus, experts say. Of course, something that smells rotten is probably going to give your gut problems. But many varieties of sickness-causing bacteria don’t smell. A better rule of thumb: After four days, toss it. And if you’re not sure how long ago you cooked it? “When in doubt, toss it out,” the USDA says.

If we’re talking marinara or other meatless sauces, you can keep eating them for 10 days after first cracking that jar. But if they contain meat, stick with the four-day limit outlined in the last section.

The Black Forest ham is on sale. Nice. Load up, but freeze anything you won’t eat within five days. That’s the amount of time your lunch or deli meat will stay safe in a fridge, according to the USDA. Frozen, it’ll keep for a month or two.

First of all, always thaw frozen meat in the refrigerator. If you warm it on the counter or in water, you’ll probably still be alright. But you need to eat that stuff as soon as it’s thawed. Experts say thawing in the fridge is safer, and if you don’t end up cooking the meat you can refreeze it once without worrying.

Refrigerated, you can keep butter for two to three weeks—longer for salted (as opposed to unsalted) butter. Eggs stored in your fridge will last three weeks.

Probably a moot point, because leftover pizza tends to disappear during your next meal. But experts say you’ve got up to four days to eat that refrigerated pie.

You’ll notice some food labels list a “sell by” date, some list a “best by” date, and others feature expiration dates. The first two have nothing to do with the safety of your food, experts say. “Sell by” or “best by” dates are determined by the food’s manufacturer, and simply mean the quality of the food could somehow drop off if you don’t eat or cook the stuff within that set period of time. The only date that matters when it comes to your risk for sickness is the expiration date you see on stuff like milk or yogurt. If you’re past that date, toss it.

Produce is a little trickier. Your safe range depends a lot on how old the stuff is when you buy it, so you really have to trust your eyes and sense of touch. If it looks or feels old, degraded, or mushy, toss it. But almost everything will be fine for a week—and apples, bell peppers, and items with a firm exterior will likely last several.

You’re all set. Keep a Sharpie and plastic wrap on hand, and you’ll never have to guess about leftovers again. Just be sure your fridge is set to 40 degrees, and your freezer is at 0. These are the temps the USDA recommends to ensure your food lasts for the time limits listed above.