Any uneaten food from a gathering should be wrapped and refrigerated after the meal and frozen within 2-3 days.
Set yourself up for future meals by freezing leftovers in strategic portions. For example, it might make sense to freeze a set meal in a container for one or two people, including a protein, starch, and vegetable, so that it can be defrosted then reheated as is. Or, consider packing a container with enough macaroni and cheese to serve as an easy weeknight side dish for a whole family.
Once you get an idea of what's left at the end of a meal, make sure you think through how to make the most of that food. It may be sending guests home with their own leftovers for lunch the next day, or planning for future meals by freezing the leftovers yourself.
