A decent standard of living
There's little argument about the minimum a human needs to survive—we know how much water, food, and shelter keep body and soul together. But a certain level of comfort above that has always been considered necessary for a "decent" standard of living. Just how much space there is between necessity and decency, though, is a social construction, and society's opinion changes all the time.
A while back, I wrote a piece on Our high, high standard of living, in which I made the point that what would have been considered a "middle-class" standard of living in the 1950s would be considered "living in poverty" today.
That piece prompted a lot of unhappy responses.
There were several who fixed on my claim that a family could get by—at that standard of living—on a single minimum-wage job, and tried to prove I was wrong by demonstrating that a minimum-wage job couldn't possible cover even the barest minimum of expenses. None of those people suggested moving to a cheaper part of the country as a way to make ends meet. Few of them stripped their supposed minimum budget of luxury items like private bathrooms and hot running water—which were by no means universal in the 1950s. Nobody mentioned being in a car pool (something which was very common in those days). Nobody mentioned moving in with their wife's parents.
The other unhappy responses, though, were from people who worried that providing perspective on just how high our standard of living was (compared to the 1950s) could be read as making the case that poor people aren't really poor, because they have color TVs and DVD players. (Apparently calling it "living in poverty" wasn't adequately clear.)
The thing is, there's no social consensus on what it takes to live at a "decent" standard of living. In fact, it's hard to even talk about, because people attack any specific proposal from both directions. Suggest that an expense is necessary to live a decent life, and people will delight in pointing out that a billion poor people around the world get by without (let's say) a refrigerator. On the other hand, chose to heat only one room of your house to minimize your contributions to global warming, and you might have a neighbor contact child protective services and call you an unfit parent.
Catherine's recent post on getting by on a six-figure income (together with its comments) vividly illustrates just how personally people take any suggestion that a particular category of expense is optional—or, contrariwise, that someone can do without it and still be considered to be living decently.
In my experience, talking about cars is the worst. People will brook no criticism of their motoring lifestyle. One of my first posts on Wise Bread made the mathematical case that its safer to live in a dangerous neighborhood than it is to have a long commute. Readers were outraged. Nobody disagreed with the math, they were just outraged. (I was amused that the suggestions Catherine saw for people trying to get by on $100,000 a year included "Drive cheaper cars," but apparently nobody suggested driving fewer cars or driving no cars.)
(I'm sure talking about children would be worse yet. There's no ceiling to how much money you can spend to give your kids "the best" and no touchstone for what's money well-spent.)
Social norms simply haven't kept up with the rapid rise in standards of living. The result is that there's no consensus on what's necessary to live decently. One person's necessity is another person's luxury, and one person's wild extravagance is another person's bare minimum for decent living.
There's a huge opportunity here for people to make their own decisions about what amounts to a decent standard of living. The key is: Do not buy into the cultural assumptions about what your particular income entitles you to—or accept that it obliges you to some particular lifestyle. Instead, make your own decisions about what standard of living you want, now and in the future. (And remember that a lower standard of living now gives you a higher standard of living later, due to interest and dividends from your savings and investments.)