The longer you leave your money at work for you, the more exciting the numbers get. For example, imagine an investment of $10,000 at an annual rate of return of 8 percent. In 20 years, assuming no withdrawals, your $10,000 investment would grow to $46,610. In 25 years, it would grow to $68,485, a 47 percent gain over the 20-year figure.

Of course, this is a simplistic example, since income taxes are not considered. However, with time on your side, you don’t have to go for investment “home runs” in order to be successful.

Fight the urge to sell when the market is volatile. What if you’ve invested $10,000 in the stock market and the price of the stock drops like a stone one day? On paper, you’ve lost a bundle, offsetting the value of compounding you’re trying to achieve. It’s tough to stand pat.

There’s no denying it — the financial marketplace can be volatile. Still, it’s important to remember two things. First, the longer you stay with a diversified portfolio of investments, the more likely you are to reduce your risk and improve your opportunities for gain.

Second, during any given period of market or economic turmoil, some asset categories and some individual investments historically have been less volatile than others. Diversification is essential to a well-designed investment strategy.

Asset allocation is the process by which you spread your investment dollars over several categories of assets, usually referred to as asset classes. These classes include stocks, bonds, cash (and equivalents), real estate, precious metals, collectibles, and insurance products.

There are two main reasons why asset allocation is important. First, the mix of asset classes you own is a large factor – some say the biggest by far — in determining your overall investment portfolio performance. In other words, the basic decision to divide your money 80 percent in stocks and 20 percent in bonds is probably more important than your subsequent decisions over exactly which companies to invest in, for example.

Second, by dividing your investment dollars among asset classes that do not respond to the same market forces in the same way at the same time, you can minimize the effects of market volatility while maximizing your chances of return in the long term. Ideally, if your investments in one class are performing poorly, you will have assets in another class doing well. The gains in the latter will offset the losses in the former, minimizing the overall effect on your portfolio.

Dollar cost averaging is a method of accumulating shares of stock or a mutual fund by purchasing a fixed dollar amount of these securities at regularly scheduled intervals over an extended time. When the price is high, your fixed-dollar investment buys less, but when the prices are low, the same dollar investment will buy more shares. A regular, fixed-dollar investment should result in a lower average price per share than you would get buying a fixed number of shares at each investment interval.

Remember that, just as with any investment strategy, dollar cost averaging can’t guarantee you a profit or protect you against a loss if the market is declining. To maximize the potential effects of dollar cost averaging, you should also assess your ability to keep investing even when the market is down.

An alternative to dollar cost averaging would be trying to “time the market,” in an effort to predict how the price of the shares will fluctuate in the months ahead so you can make your full investment at the absolute lowest point. However, market timing is generally unprofitable guesswork. The discipline of regular saving is better.

Unless you plan to rely on luck, your portfolio’s long-term success will depend on periodically reviewing it. Maybe your uncle’s hot stock tip has frozen over. Maybe economic conditions have changed the prospects for a particular – or a whole class of — investment.

Even if nothing bad at all happens, your investments will appreciate at differing rates, so after a while, your asset allocation mix will change. For example, if you initially decided on an 80 percent to 20 percent mix of stocks to bonds, you might find that the total value of your portfolio has become divided 88 percent to 12 percent. When that’s the case, you’ll need to rebalance your portfolio.

Notable Quote: “Our favorite holding period is forever.” —Warren Buffett

Tom Mills is a Registered Investment Advisor and Certified Financial Planner®. If you have questions or topics, call or write him at 1030 Seminary St. Suite D, Napa CA 94559, 254-0155, fax 254-0158 or e-mail suntrm@aol.com