I would throw out an unopened jar of Dukes for a half-eaten jar of Miracle Whip. As for leftovers, we sent about all of them home with the son and finished off what little was left on Friday. Now I have room for my pumpkin dump cake!
I just don't do leftovers, period. 24-72 hour old food just isn't appetizing to me. The wife knows after 47 years, that if there is left over food and she isn't going to eat it…..not to even think about putting it in the fridge. I have delicate tastebuds.
Three day is too conservative. A week is fine assuming proper refrigeration and reheating. When reheating only reheat what you're using, as in only reheat once. Always bring back up to full temp.