Most of what people buy is not necessary. I am going to define necessary as items and requirements for survival, rather than thriving. Luxury items are not necessary. Good examples of luxury items would be fancy clothes, smartphones (and pretty much every electronic device for that matter), and entertainment devices. Now, the line between necessary and unnecessary is quite blurry. Necessary items could also include items used to make money, or for necessary work. If I am a painter and I need to buy a paintbrush to finish my work to earn money to pay for other necessities like food and shelter and clothing, than that paintbrush is a necessary purchase. There are also purchases for health items, like medicine. Medicine and prescriptions would be a necessary purchase. Purchase of a car would fall into the same category as the paintbrush. You don’t need it for survival, but you need it to earn money to buy the necessary items. Clothing is necessary, but fancy expensive brands are generally not. You need to have clothes, but it can be a very basic wardrobe, so clothes are only a necessary purchase if you are unable to wear the ones you owned previously. An item that would be on the line would be electricity. Almost every person in the United States has to pay an electric bill. Electricity is not necessary for survival, but it is very important for comfort. I would say electricity is necessary because you need it for basic comfort, it lets you stay warm in the winter and cool in the summer, and lets you see in the dark, keep your food cold, and much more. Overall, I would say that most of what people buy is not necessary. Most purchases are luxury items to make one more comfortable or happy, at least in theory, and not necessary.