The type of refrigerator a homeowner chooses depends largely on the size of the household, what that household is used to eating, whether it want a French door fridge or second hand, whether it likes homemade food or takeaway and how much the family entertains.
Choosing a refrigerator is especially important because a refrigerator uses a surprising amount of energy. A refrigerator operates very much like an air conditioner in that it removes heat and moisture and suppresses the growth of bacteria. This is a complicated system and because of that the refrigerator can represent as much as a quarter of the household fuel bill. So refrigerators need to be energy efficient as well as appropriate for the household. One good rule of thumb would be to have 3.65 cubic feet of space for the Mum and Dad and 1.2 cubic feet for each of the kids.