Wilfsell - re "if no-one can judge need objectively, how best can we judge it and on what criteria?"
We can't. That is the point.
That is why nobody in their right mind (in politics, at least) tries to determine what everyone needs, because there is no such common denominator once we are out of the realm of food, shelter, clothing.
Books might be inessential to you. To me, they may the purpose of life. Bicycles might seem completely pointless to me, but riding a bike might your one true hobby, what gives you most joy. I think a good school is an absolute need, but there are some here who prefer to home school their children etc etc.
That is why money is a good medium - you work, receive money in return, and then go spend it according to what you feel you need.