If you're relatively young, you might not be giving too much thought to saving and investing, and you might not be thinking much about your retirement, either. It makes sense: After all, you're probably relatively early in your career and you may not be making nearly as much as you expect to in the future. And if you're, say, 30, it can be hard to imagine being 60.

But there are some powerful reasons to start learning and investing sooner rather than later. For one thing, you have a huge advantage over many other investors right now. Also, if you turn out to be really good at saving and investing, you might get to retire early -- well before age 60 or 65 or 70; you might retire at 45 or 50 or 55!

Someone is smiling and pointing up and to her left.

Image source: Getty Images.

1. Start investing early

Your big advantage over millions of other investors is time. A 50-year-old may be earning more than you (though perhaps not!), but they only have 10 or 20 years or so until retirement. If you're 30, you have 30 or 40 years in which your invested dollars can grow.

Check out the table below and see what a difference there is between your money growing for 20 years and 40 years -- you don't end up with twice as much money, but more than five times as much:

Growing at 8% for

$7,000 Invested Annually

$15,000 Invested Annually

5 years

$44,351

$95,039

10 years

$109,518

$234,682

15 years

$205,270

$439,864

20 years

$345,960

$741,344

25 years

$552,681

$1,184,316

30 years

$856,421

$1,835,188

35 years

$1,302,715

$2,791,532

40 years

$1,958,467

$4,196,716

Data source: Calculations by author.

The sooner you start investing, even with somewhat small sums, the sooner those dollars can start growing for you. And your earliest invested dollars are your most powerful ones.

2. Invest effectively

You'll note that the table above reflects money growing at 8% annually. That's because the stock market is arguably the best place to grow your long-term money powerfully. The stock market's average annual return has been close to 10% over long periods, but it could be greater or less than that during your particular investing period. So the table uses a more conservative growth rate.

If stocks are your best bet, how should you invest in them? Well, you have some choices. Low-fee index funds are the best strategy for most people, as they can deliver returns that roughly match the stock market's return (which can be 10% annually, remember) with little effort from their investors. You just buy shares (and keep buying shares) and then be patient -- for many years.

Here are three solid index funds to consider:

  • SPDR S&P 500 ETF (SPY)
  • Vanguard Total Stock Market ETF (VTI) 
  • Vanguard Total World Stock ETF (VT)

Respectively, they'll park your money in roughly 80% of the U.S. stock market, the entire U.S. stock market, or just about all of the world's stock market.

If you want to aim for market-beating returns, you might opt to add some growth stocks to your mix. Growth stocks belong to companies growing at faster-than-average rates. They can be more volatile and risky than average stocks, but they also have the potential to increase in value at a faster-than-average rate.

Dividend-paying stocks can also be powerful growers, offering regular payments during good times and bad, with those payouts often increasing over time.

If you're going to invest in individual stocks -- which you can do along with index funds -- take a look at our Motley Fool investing philosophy, which suggests buying 25 or more stocks while aiming to hold them for at least five years.

3. Invest regularly

Finally, be diligent. Save and invest regularly, year in and year out -- for decades, if you can. The more you save and invest, and the earlier you start, the more wealth you can amass.

It can be easy to give up if the market or your particular stocks don't surge soon after you invest, but trust the process. The market will go up and down over time, but over the long run, it has always gone up. Review that table up top, and you'll see that the really big bucks arrive after you've been saving and investing regularly for a decade or three. This kind of diligence has the power to get you an early -- or at least earlier -- retirement.