I have to plan, otherwise it's too darn easy to run through the White Spot drive through on the way home after a stressful day (aka every day...mm... bacon cheeseburger, best fries in the world, and a coke... 1200 calories later...)

I have 3 "regular" breakfasts that I choose from, salad for lunch every day, and switch up dinners + dessert every week.
Meal planning can be a challenge since DH is a vegetarian + most soy/bean/lentil/etc products and my tummy tend to disagree violently. So, our meals tend to be based on elements that are share-able/veggie but we do our own proteins. It's kind of a pain, but prepping two meals is just not gonna happen at the end of the day, and it would be so wasteful - it's hard for us to use up groceries to begin with, without careful planning it would be a nightmare.
I used to be anti-planning for food and just relied on whatever I was craving at the time. Then I realized that this led to snarfing down fast food on the fly because it was "too much time and trouble" to go to the grocery store when I was hungry, and meanwhile the bits and pieces of meals in the fridge would go to waste because none of them would add up to a proper meal - but they seemed like a good idea when I was browsing the grocery store without a plan. Ack. Vicious cycle!