But there is another compelling reason to get into the habit of saving. (Here is where this column also turns into advice for the older folks who are giving you this to read.) People who save a lot get used to a lower rate of consumption while working, so less money is needed in retirement.

Stretching to save a little more yields a double dividend. You accumulate more assets and you lower the amount you will need in retirement because you will not have the habit of spending extravagantly to feel fulfilled.

Inevitably though, we return to the question: How can you possibly afford to put away that much? If you are only making $40,000, a not-untypical starting salary for a college-educated professional in a big city, the weekly gross of $769 works down to $561 in take-home pay after income taxes and payroll taxes for Social Security and Medicaid.

Were you to divert 10 percent of your salary to a 401(k) plan, the bottom line becomes $509.

In other words, a regular habit of savings costs you $52 a week. You easily frittered that away last week on things that you cannot even recall this week. A useful exercise that proves the point: For a week, try to list everywhere you spend cash or use your credit card.

Could you save another 10 percent a week, or $50? If you do, you are nearly set for life.

Can you live on $1,950 a month? Rents being what they are in certain cities like New York, San Francisco or Washington, sure, it will be tight. People do it by finding a roommate and watching their expenses (or asking for an occasional handout from Mom and Dad).

There may be another compelling reason to save and that is that while many aspects of retirement savings are predictable, the big unknowable is health care costs. “If you believe in the logic of the life cycle model, then once you get used to peanut butter, all else follows,” said Jonathan Skinner, a economics professor at Dartmouth College who has studied retirement issues and recently wrote a paper titled “Are You Sure You’re Saving Enough for Retirement?” for the National Bureau of Economic Research. “That’s the assumption that I am questioning: Do people want to be stuck in peanut butter in retirement?”