I'm not religious about doing this, but I find that when I plan what I'm going to make for dinner each night at the start of the week, I can cut down my grocery shopping bill. But I find that I keep overestimating how much we eat and I can actually just make 4 dinners a week with leftovers on the other nights.
My DH thinks I'm anal with my little blackboard in the kitchen looking like some kind of bistro menu board outlining the meals for each day of the week - and friends who come round find it hilarious. But it helps me feel organised Surely I'm not the only saddo who does this?