The point of a refrigerator is to slow the growth of bacteria on foods. The point of a freezer is to stop the growth of bacteria completely. If we could, I’m sure that we would freeze everything that we could so that it would last longer, but some goods don’t do so well after being frozen and then thawed. Fresh food also tastes better and is more nutritious.
The perfect temperature for a refrigerator is somewhere between 35 and 38 degrees. If the refrigerator is set any higher, the food will spoil at a much faster rate. Any temperature below 35 degrees will cause the food to freeze. All of which are major problems. The freezer should be set between 5 and 0 degrees. Running the freezer colder than 0 degrees will generally be a waste of energy and you will see no real benefit. Running the refrigerator or freezer at the proper temperature can reduce energy usage costs. The unnecessary expense of replacing spoiled food or fresh produce that has been frozen will be also reduced.