We Americans are a funny lot. For all our professed love of personal responsibility, pulling oneself up by one's own bootstraps, etc., we don't really act on those convictions. You need only look around at the state of the national savings rate to tell that many of us can no longer make the distinction between need and greed.

The other day, I read a very scary newspaper article about a family with several kids and less than $10,000 in college savings -- yet the queen of the castle had to have one of GM's (NYSE:GM) $50,000 SUVs. And she had to have the 4,000-square-foot house from Toll Brothers (NYSE:TOL). None of this was negotiable. I hope her kids all become rock stars, because the family's going to need the money.

Never mind that the family would have trouble paying for her -- I'm going to call a spade a spade -- greed. The solution was simple: Borrow some more of that cheap money, and spend everything that's coming in. That means save little or nothing, which can mean major trouble come retirement time.

I'd love to believe that this is some kind of anomaly, but as Robert Brokamp discusses in his Motley Fool Rule Your Retirement newsletter, it's not. We get reminders every day. Recent concerns from Fed Chairman Greenspan about housing bubbles and savings rates are just more evidence that we're mired in a buy-now, pay-later, and future-be-damned mindset.

And it's not just the young who have their heads buried in the sand. I meet people all the time who are only 10 or 15 years from retirement, who somehow have far less packed away than my wife and I do. Without giving away too much, I'll tell you that our earning power as a writer and a teacher is quite modest. We're hardly pulling in the big Benjamins, and these slim-savings acquaintances know this, so the question they always ask is, "How do you do it?"

Granny can help
It's very simple. We know the difference between need and greed, most of the time, anyway. When in doubt, I channel a stern-looking Midwestern grandma of yesteryear -- someone out of Grant Wood or Steinbeck -- and imagine what she would say.

When I was jonesing for a new MP3 player, I heard Grandma Pennywise screeching at me about the sheer waste of those dag-blasted noisemakers. In the end, I overruled her blanket prohibition against "ear-busting radiolatrons," but I did look past Apple's (NASDAQ:AAPL) iHype and saved $70 by grabbing a comparable model from SanDisk (NASDAQ:SNDK). But that's just elementary penny-pinching.

It's not just the big-ticket mistakes that set us back. It's perennial spending on things we don't need that keeps us poorer now, and could make us really poor when our working days are done. The way to make sure you rule your retirement is to engage in systematic saving, month after month.

Baby steps
Everyone needs to buy a bit of gasoline for those trips to the grocery store, right? That's why Exxon Mobil (NYSE:XOM) is so huge. Some expenses are unavoidable, but how about earning a 5% rebate on all the gas and groceries you buy? A dividend card from Citigroup (NYSE:C) will get you just that. And take a hard look at the rest of your life. Do you need premium cable? Starbucks every morning? Fast food for lunch?

If you think these are little things that don't add up, you're mistaken. If you need to see the math, and you've got Excel from Microsoft (NASDAQ:MSFT), you can download a simple but powerful free tool to see just how much the little things add up.

The lifetime savings calculator lets you see the impact that even a small shift in financial attitude can have on your future fortune. I ran some numbers from the cost-savings program at my own house and assumed a moderate 10% annual return on the savings, and the table below shows the results after 10 or 20 years. A few small changes can produce a spare $500 a month. And that can really add up, especially if you shuffle the difference into a tax-free retirement account, as we do. So, without further ado, I present to you a small table that shows you how much richer you can become if you make only a modest effort to differentiate between need and greed.

Change Savings per month 10 years 20 years
Small, local beer instead of pricier brand $24 $4,590 $16,495
5% back on gas and groceries $20 $3,825 $13,746
Basic cable instead of premium $35 $6,694 $24,055
Thermos o' homemade brew instead of daily Starbucks $70 $13,388 $48,111
Leftovers for lunch instead of McDonald's $100 $19,125 $68,730
Used cars instead of shiny new ego-mobiles $250 $47,812 $171,825
Totals: $499 $95,434 $342,962

As you can see, the key is not only discipline but also time. The sooner you start saving, the more time the magic of compounding will have to make you wealthy.

And take a look once again at the items in that table. I think most would agree that this kind of minor penny-pinching will hardly make you into a hermit now. But if you don't make a few sacrifices and bank the savings, you very well may be forced to live like one later.

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If you're looking for other ways to plan for a better life down the road, take a trial of Rule Your Retirement . It's on the house.

Seth Jayson plans on an early retirement, so he can have more fun. At the time of publication, he had shares of SanDisk but no positions in any other company mentioned. View his stock holdings and Fool profile here . Fool disclosure rules are here .