It depends a lot on how varied a menu you want/require (or your spouse does....)

Cooking with variety (or "buy whatever's on sale") is really hard if you also want to do it cheaply (minimize waste & spoilage, especially). Cooking the same few meals, maybe with some seasonal rotation, is easy because you can get the measurements of what you need each week ver exact to keep spoilage very low, and arrange them so waste from one meal always goes into another later in the week.