This is the worst bear market that a lot of people have ever seen. Everyone from those close to retirement to people just starting in the work force have gotten into stocks in a big way over the past couple of decades.

Even as your spirits drop along with the Dow Jones Industrial Average, here are five things to keep in mind as you look at your portfolio.

1) DIVERSIFY

Diversification is so important, it can’t be emphasized enough -- so it seemed like it was worth capital letters up there. We get more emails at FOXBusiness.com than you’d care to know from people detailing their stories about retirement money invested, say, all in Lehman Brothers bonds. (Lehman, of course, filed for bankruptcy recently – so those bonds may return something, but not as much as people thought they’d get.)

If you’re investing in individual stocks or bonds -- anything that could be wiped out if a company fails -- you should probably try to diversify as soon as possible.

“The more diversification within an asset class, the safer you are; and the more asset classes you have, the safer you are,” said Gary Greenbaum, a fee-only financial adviser with Greenbaum & Orecchio.

Unless you’re invested in something backed by the U.S. government (because we’ll all have bigger problems than this if the government fails), you cannot assume it’s a sure thing.

If you have your entire portfolio in less than 20 components or so (and that’s specific companies, not, say, a mutual fund that might be in 100 companies), you almost certainly want to check around to figure out how to diversify. Your future is far too important to trust to a small handful of company stocks or bonds.

2) You Don’t Lose Money Until You Sell

Research shows that individual investors tend to sell when stocks are low and buy in when they’re high -- exactly the opposite of what will earn you maximum returns.

As hard as it can be to see stocks at these levels, remember that these are losses on paper only, until you sell.

“Five years from now, buying at these depressed levels, people are going to be enjoying the fruits of their decisions,” said Marc Schindler, a financial adviser with Pivot Point Advisors. “If people are getting out of stocks, they could regret it later.”

Since it’s almost impossible to time the bottom (or the top) or a market, you won’t necessarily know when to get back in, either. When markets hit bottom, they tend to rebound quickly, so you could lose a lot of good upside, too.

3) Be Careful Who You Trust

There are different types of advisers, and some don’t always have your best interests in mind.

For instance, if you go into your bank seeking to invest in something safe, you may get someone who isn’t just a banker, but a broker, too. A lot of advisers out there will get a commission if you buy certain products.

“If you want to be safe, you should get advice from people with two characteristics: one, that they have no conflicts of interest; characteristic number two is that they are competent,” Greenbaum said.

One place to go would be the National Association of Personal Financial Analysts, whose members are compensated solely by their clients, not through such things as commissions, rebates or finder’s fees. That way, you can be assured your financial adviser is working for you -- and not for the company whose products you’re buying.

You can find NAPFA members through the group's Web site by filling out a short form. 

4) Concentrate on What You Can Change, Not What You Can’t

No regular person is going to be able to change the markets -- Warren Buffett couldn’t even do it with his buys into General Electric (GE) and Goldman Sachs (GS).

But, you can change things like making sure your bank deposits are fully insured by the Federal Deposit Insurance Corp., checking for proper diversification, and perhaps even rebalancing your portfolio.

“It’s always a good idea to go back and look at the overall asset allocation -- and [ask] are you willing to give up some returns for some extra stability,” said Georgia Bruggeman, a financial adviser with Meridian Financial Advisors.

5) For Long-Term Money, Don’t Check In Every Day

If you check your 401(k) balance every day, you could drive yourself insane the way everything’s bouncing around each trading session.

Stop it.

“You cannot watch the daily stuff -- it’ll give you an ulcer,” personal-finance expert Dave Ramsey told FOX Business recently.

If you’ve invested the money for the long term, just let it ride. Markets go up and markets go down. And if you find that you can’t stomach this level of losses -- remember in the future that your risk tolerance isn’t good enough to be heavily invested in stocks.