Yikes! 90-Year-Old Doctors and Mechanics?

Think about the future for a while, and you may conjure up images of a fantastic place where people live happy, long lives -- where we travel around in hybrid hovercrafts and go to nearby planets for vacations.

But after reading a piece by Peter Thiel at Forbes.com, I had another vision of tomorrow. Theil wrote: "The nation now spends more than it makes, which means that not only do most Americans plan to work until they die, they plan on putting in a little afterlife overtime. A nation of nonagenarian welders and bank tellers would be terrible, but if the nation doesn't start saving more, that's only the least bad outcome out of many."

Scary, eh? And Thiel wasn't spinning a science-fiction scenario; it's not entirely unreasonable to picture a future full of extremely wrinkled cashiers and lawyers and teachers. Far too many Americans are indeed not saving and investing enough. Far too many are counting on Social Security and puny retirement accounts to do more than they'll be able to. These are the folks who may end up realizing, around age 60, that they just can't afford to retire.

According to Thiel, the median American household has just $37,000 in assets, other than a home. Even those closest to retirement have surprisingly little saved -- the oldest Boomers have about $180,000 to their credit. That's nothing to sneeze at, but consider that Thiel goes on to say that $180,000 produces an income of just $750 a month.

Let's examine these numbers a bit, using some information I've gleaned from the Fool's Rule Your Retirement newsletter service: In order to make your nest egg last, you should conservatively plan to withdraw about 4% of it per year in retirement. So if you've got $180,000 socked away, you can hope to take out $7,200 per year on it. Can you see yourself living well on $7,200 per year? Divide that by 12 and you get $600 per month, not $750. (Thiel must have been assuming a 5% withdrawal rate. That isn't uncommon, but it leaves the retiree with more of a chance of running out of money before running out of breath.)

If there's any silver lining in all this, it's that your future doesn't have to end up bleak, with you punching a time clock as you approach your 100th birthday. If we take some time to learn more about retirement planning and we start socking away some significant sums as soon as possible, invested in sensible and tax-efficient instruments, we can improve our tomorrows today.

Stocks can help us with this, as can top-notch mutual funds. Check out the average annual growth rates of some the following mutual funds over the past decade:

Do yourself and your loved ones a big favor: Tend to your future. You can learn a lot about retirement planning in books available at your local library and also here at The Motley Fool. (Visit our Retirement Center for more info.) I also invite you to test-drive, for free, our Rule Your Retirement newsletter. Doing so will give you access to all the past issues, which feature, among other things, a host of "Success Stories" profiling people who retired early and have shared their strategies.

(Consider forwarding this article to anyone whose retirement you care about. Just click on the "Email this Page" link near the bottom of the page.)

Longtime Fool contributor Selena Maranjian does not owns shares of any company mentioned. The Motley Fool has a full disclosure policy.