Do Economic theory really apply on our daily life,e.g utility?

Question

Do Economic theory really apply on our daily life,e.g utility?

Answer 1

yes

Answer 2

Yes.  Whenever you buy something that item minus its cost brings you more utility than having the money and not the item.

Answer 3

Yes, each time you made consumption, purchase, investment decision - you decide for yourself if you will benefit from acquisition of certain good/service and if this utility will be more than cost of acquisition.