I plan but allow room for flexibility. Some people can tell you now what they will have for dinner on Friday night, but something in me rebels at that level of planning. So when planning a week's menus, I have everything that I need to stay op but have not detailed exactly what I will eat when. Of course, some of my food, such as fresh fruits and vegetables, will drive my choices.
One thing that I learned from someone here at 3fc (probably Robin?) has been a huge help to me. I have a plan for dividing my calories throughout the day.
Breakfast - 200 calories
mid morning snack - 150 calories
Lunch - 400 calories
mid afternoon snack - 150 calories
Dinner - 400 calories
evening snack - 150 calories
I have two breakfasts that I switch between. I have always tended to eat the same breakfast, so that does not bother me. I have several 400 calorie meals that I juggle around and always keep the ingredients for those. These are the core of my plan and I must keep these things in stock at all times! I have a standard shopping list that includes these items. I think of it as planning not to plan because I can switch the meals around depending on my mood. It also helps at home to be able to offer DH meal x or meal y for dinner. (He has lost 10 pounds with no effort.)
Then I have the meals that are a little different and require more planning. This is typically when I am trying something new. For these, I have to plan time for cooking as well as having all the ingredients on hand. Some of these meals move into my standard list, some do not.
My eating/cooking, even thinking, now is so drastically different from my last 54 years that I have to be organized and plan or I just can not succeed.
*Just read what was posted while I was writing. Many posters can say in a few words what takes me several paragraphs.

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