Running list here too, on the counter all week. That way anyone can add to the list without having to track down the phone with the APP on it. We grocery shop on Sunday morning, and while we drink our morning cup of coffee we check cabinets and the fridge before heading out.
And we go down every isle in the store to help remind us of things we may have forgotten, or to seek what sale items are on that aisle.
We tend to meal plan for the next week's dinners based on what is on sale at the store that week. It normally will be one meal of whatever fresh fish, beef, chicken and pork cuts are on sale that week. We always have Schwans pre-cooked hamburger patties, Schwans breaded fish fillets, and eggs on hand for quick dinner items if we come up short.