Why would you tell someone who isn't sure how old the leftovers in the refrigerator?

If someone isn't sure how old the leftovers in the refrigerator are, I would advise them to prioritize food safety. It's best to err on the side of caution; if the leftovers have been in the fridge for more than 3-4 days, it's safer to discard them. Additionally, they should check for any signs of spoilage, such as off smells, changes in texture, or mold. When in doubt, it's better to throw it out to avoid the risk of foodborne illness.