I have a confession: I don't plan my menus. There. The cat is out of the bag. But I have learned that I don't need to plan menus. Why? Because I keep a well stocked pantry, refrigerator, and freezer. All I need is just one inspiration sometime during the day to decide what to make for dinner. The rest of the dinner menu falls into place after that, depending on what we have or what needs to be used, or what "goes with" the main course planned.
Now, my children would argue that the refrigerator is never well stocked, because they usually can't simply reach in and grab some exciting food item, ready to pop in the mouth. They accuse me of buying ingredients, not food. And they are mostly right. But, I tell them, the possibilities are there. Be creative.
Their argument aside, I really do keep a lot of food on hand. I stock up when groceries we use are on sale. I buy in bulk. I refresh the supplies before we are fully out. And, using what we have on hand, I make varied and nutritious meals every day. When I say varied, I mean varied in the outcome, not necessarily varied in the ingredients. For example, I don't buy a big variety of proteins; ground beef and ground turkey, chicken, eggs, beans, and sometimes pork (roast or chops) about covers it here. But there are hundreds of main dishes I can make using one of these proteins as the starting point.
In the pantry, I keep: various flours and sugars, oats, whole wheat berries, pastas of many kinds, rice, taco shells, powdered milk, dry beans, barley, canned tomato products of all kinds, canned beans, corn, and mushrooms, canned tuna, chicken, and roast beef, canned fruits of several kinds, juice sometimes, dried fruit, jams, broths, mushroom soup, tomato soup, canned milk, honey, molasses, nuts, popcorn, graham cracker crumbs, cake mixes, jello and pudding mixes, chocolate for baking, shortening, sprinkles, and a wide variety of condiments, vinegars, oils, and seasonings. Now and then I buy cereal, crackers, chips or granola bars, but only when they are dirt-cheap.
My u-shaped pantry is only 3 ft deep and 5.5 ft wide, but it holds A LOT (the top three shelves don't show in the pictures):In the freezer, I keep: meats (listed above), vegetables without sauce, whole berries, sliced peaches, bread on sale, coconut, nuts, and yeast. Sometimes we also have casseroles, sausage, bagels or English muffins, ice cream, and butter.
The refrigerator usually holds: leftovers, milk, fresh fruit and veggies, eggs, cheese, yogurt, sour cream, meat to use this week, lemon juice, margarine, corn meal, sourdough starter, ice water, and condiments and dressings.
With such a stock of food on hand, rarely have I had trouble deciding what to make for dinner. So I see no reason to plan menus every week.