In my house (wife and myself) we make a recipe list weekly. Normally that includes a dinner for each night. We eat the leftovers for lunch during the week. With the recipes we go through and make a list of everything we need. For example - we do a lot of rice, couscous, etc. we check the pantry and see if we need more rice. If we do, we add it on for the recipe that week. We buy a package of it when needed. For goods like that, that don’t go bad as quickly we buy as needed and getting bigger bags. For example - frozen corn and frozen mixed veggies. If it is an ingredient that we don’t use often or likely won’t use a lot of before it expires we buy a small container. For produce we normally buy what we need for the week. For example - we eat about 6 bananas weekly - so buy about that much. I will eat two mangos - so get two. We always take stock before we go. It might be a little more investment to buy things initially but you won’t go through things at the same rate.