There are a lot of choices in a grocery store today. Every item comes in different sizes and different brands. Do you want the giant size or the small size? Is it better to buy the name brand or the store brand? With so many choices, it can sometimes be overwhelming when you are trying to shop.
One of the choices that you have to make is what size of an item to buy. Is the smallest size the best? Or should you buy the biggest size that the store has? The biggest size would last the longest. That means you wouldn't have to buy the item again for a while.
When you are choosing a size, think about how much room you have to store it. If you live in a small place without a lot of cupboards, you may not have room for the large box. Leaving a lot of boxes on the counter will take up space.
Also think about where you do something. You may have to go into the basement or to another place to do your laundry. The big bottle of detergent might be on sale, but do you really want to have to carry something that big? The smaller size might be a better choice.