It would be GREAT if they would let you know their plans the night before and then not change their minds.
I have had guests tell me as they head out the door in the morning that they are saving me work by not eating. They believe this. Depends on what I was planning to serve whether or not there is saved effort or not. If I've been waiting and have everything set to make, it's kind of a pain. But worse is when they just slip out the door without saying goodbye. Most things I cook up as the guest comes in like waffles or pancakes or eggs.
Quiche is another story. And I will eat two day old quiche cuz I do love it! Can you freeze and reheat quiche?.