I have a friend who recently crossed the big 4-0. Forty years of age. He was more than a bit depressed about it.

"Look, Dwight," I said -- which didn't make much sense since his name isn't Dwight -- "Getting old sucks. No one wants to get old. But you know what's worse? The alternative. If you think about it, growing old is a heck of a lot better than not growing old."

We are all aging. Some of us have practiced at it harder than others, but for each of us, the passage of time is relentless. The lucky ones among us are going to grow old.

Old is the new "not dead"
Fortunately, that's more and more of us, as the life expectancy of people in the United States continues to climb higher on the backs of technological and medical advances. There are some fantastic investment possibilities surrounding the rapidly increasing number of elderly Americans, none perhaps better than the combination of Elan (NYSE: ELN) and Wyeth (NYSE: WYE), which have an extremely promising new compound for the treatment of Alzheimer's disease that they hope to bring to market. Other potential investments include prosthetics manufacturer Stryker (NYSE: SYK), travel giant Carnival (NYSE: CCL), robotic surgery pioneer Intuitive Surgical (Nasdaq: ISRG), and even voice technology giant Nuance (Nasdaq: NUAN).

But investing in equities based upon rising life expectancies around the world isn't the same as putting together a plan for your own old age. And now that I've laid out the alternative, I ask again: You do want to grow old, don't you?

Of course you do. And that's why you, like all of us, need a plan. And while many people are happy to charge you a lot of money to advise you on this plan, a comfortable retirement is not very hard to achieve for most Americans.

For that you can thank your government
Seriously. Retirement planning has been so much easier since tax reforms created Individual Retirement Accounts. These are the Most Valuable Players in the whole retirement game. You should fund them every year, as early as possible in the year. Don't wait until the last possible moment. Do it now.

Over a 20-year period, the difference between funding your IRA every January and waiting until the following April (as the law allows) is astounding, a difference of $12,000 at maximum funding levels. And it will be even higher as the annual investment limit increases this year from $4,000 to $5,000.

I cannot emphasize this more highly: One of the greatest things you can do to prepare for your retirement is, in fact, anything -- just so you do it soon. When it comes to compounding interest, procrastination is extremely costly.

So is it too late for me?
Several years ago, AARP put out a study called "Beyond 50," which found that the lowest quartile of wage earners aged 50 to 61 in the United States had saved, on average, $6,000 for their retirements. That's not going to get it done, and we're frankly terrified for these people. Lots of Americans have failed to save for their later years, and with longer life expectancies, we can expect to see more people remain in the workforce well after retirement age, not because they want to, but because they have no choice.

But even at 50 years of age, maximizing your IRA contributions into a conservative fund, into some high-quality companies like Johnson & Johnson (NYSE: JNJ), can have a monumental impact on your quality of life after 70. After all, that's 20 years, and the law of compounding doesn't care how old you are. If you start earlier, it would require some effort on your part not to have a healthy retirement account.

An IRA is no place for moon shots
Notice that I used the word "conservative." By this I mean that while many people use an IRA to make speculative investments, if this is money you will absolutely depend upon for retirement, you should make absolutely sure that it will be there when you actually do retire. After all, for every Nuance there are frauds like Lernout & Hauspie. For every Abercrombie & Fitch there are struggling retailers like Gap. The amount of money you can invest in the market is unlimited -- the amount you can put into tax-deferred IRAs is not. Keep your play money and your retirement money separate.

Want a leg up?
One thing that I like about the retirement message is that it is one of the few investing pursuits that starts with an end goal in mind. Sure, you can invest your entire life, but what you're really seeking to do is to ensure that the day you stop working isn't one that strikes fear in your heart. Being wealthy gives you options. Being comfortable does the same. My colleague Robert Brokamp runs a fantastic service called Rule Your Retirement to help you get on track. Think you're too young to plan for retirement? You're not. Think you're too old to make a difference in your standard of living in your later years? Pshaw!

A 30-day trial to Rule Your Retirement is free. No, seriously. It's free. Just click here.

Bill Mann owns shares in Elan. Intuitive Surgical is a Rule Breakers recommendation. Nuance is a Motley Fool Hidden Gems recommendation. Johnson & Johnson is an Income Investor selection. Gap is a Stock Advisor and Inside Value selection. The Fool has a disclosure policy.