People differ! One person's preference is another's nightmare. My beloved Martie bought these books on how to be organised and then becomes depressed that she cannot be as organised as prescribed. I keep on telling her "darling, relax, that is not how you do things". Before buying that book or trying that magazine article on how to organise your life, get to know yourself. What makes you tick? Another person's mess might be your happy place.
I've many times took my mother-in-law buying her necessities. With her walker (three-wheeler) she would take off in this direction and then in that direction, driving me nuts. I prefer starting at the far end of the supermarket, consulting my shopping-list every so often, snaking through the isles—doing the fridge and freezer lanes last.
As teenager, I made my parents a paper-roll grocery note-board: I took a rectangular piece of wood, sanded and varnished it; I took piece of steel wire that I bent in a square, with part of one side missing—secured the horizontal side on top with U-shape pins into the wood and inserted over the bottom horizontal side a role of calculator/cash register paper. I allowed below the roll sufficient space for writing and at the bottom end of the plank I mounted a horizontal strip of metal to serve both to hold the loose-end the paper roll and to tear off. I mounted on the side a clip to hold a pencil and at the bottom a paper-clip to hold pieces of paper. About 35 years later, I salvaged the grocery-list feature from my parents' retirement unit when my mother moved into an old-age home (my father passed away about four years ago).
What works well for us, is to record items as they need to be replenished and to take this list along when doing shopping. We used to list on square paper pieces and keep the list in a cube-clip (we have now converted to the paper-roll). When I go grocery shopping—usually once a week—I take the list with and further use my discretion. I would replenish basics (such as eggs, cheese, self raising flower, etc.) and look at the vegetables in season and buy variety. I further by fish, chicken and occasionally red meat. Then there are the regulars, such as yogurt, milk, salad ingredients and fresh fruit.
Martie has many times suggested that we draw up a menu for each week and then buy groceries accordingly. However sound this idea, we never do get round to execute the idea. I prefer the notion of a selection in the fridge and cupboards—when dinner time, I would look in the fridge and decide what to cook. I try to make sure we eat a balanced diet. When entertaining, I would give consideration to the menu and make sure a buy what is needed.
When you have small children, make sure you buy child-friendly food, but check the ingredients. Remember to buy suitable provisions for lunch boxes, etc. I always felt is better to have a small supply of treats hidden in the cupboards than having the mission out when treats are called for.
When on a tight budget, it is best to upfront decide what is necessary and then only buy those items.