Write It Down: Parties
I keep a simple list of everyone who comes to my house for a meal, when the meal was, and what was served. I feel that since I can prepare hundreds of different recipes, why should I serve the same dish twice to the same person? My guest list also provides a list a past meals served so I can easily serve the same menu to different guests, if that is what I wish to do.
Another great reason to write it down: you can keep track of what you've already cooked.