When it comes to investing, we sometimes forget about the clock. Or as the pros call it, the investment time horizon.
That's unfortunate, because "it's incredibly important," says Cody Willard, an investor in Alto, N.M.
The time horizon is a guide investors use to decide how long to hold an investment. You should make the decision "before you move any money around," says Mr. Willard.
For traders, time horizons can be short—sometimes a matter of hours or days. But for most investors, they are much longer.
A trader may make a bet based on economic data due out a week from now. When the news breaks, the trade is either successful or it isn't. Either way, the position should be closed out.
Failure to close a position within a predetermined time is one of the biggest mistakes a trader can make, says Mr. Willard. That's when a losing trade gets turned into an "investment," he says.
For retirement planning, time frames are necessarily longer. A 30-year-old man should have a time horizon of at least 50 years. Even if you retire at 65, you need to consider that you'll likely be living into your 80s, so your assets will need to be invested for a long time.
Over such a long period, the relative volatility of stocks versus bonds or cash doesn't matter since there is plenty of time for the price to recover.