To all of you—of all ages—who have written to me about pulling your retirement savings out of the stock market, I have a one-word answer: “Don’t!”

Even if you’re very close to retirement and are feeling this market hit more than anyone else (as you should be), remember: Even though most of us have never seen anything like this, retirement investing should be determined by two things: your timeline and your stomach, not what the market's doing.

If all these Wall St. shenanigans has you doubled over, pull back slowly from the market to shift your assets into something closer to your comfort level. Just know that if you put all your money into bonds or T-bills and you have more than 10 years until retirement, the price you’ll pay for safety could be losing out on double-digit growth over time.

The younger you are, the more it should be about growth—take the risk of putting the majority of your money in the market. The closer you get to retirement, the scales should tip toward protecting what you've got—which means locking in a bigger chunk of your money in what will preserve what you've put in, but may earn you lower returns. Of course this is a market such as we've never seen, hence the tried and true rules of long-term investing could use some revisiting—our gut has rarely, if ever, been so tested.

Here’s a demo-to-demo nugget of direction on long-term investing these days, and remember, NO individual stock investing! Unless you can afford to lose it. In that case, gamble away:

20-somethings: Coming in at the bottom (or close) makes your money work for you - harder. The biggest hurdle: Getting you to sign up for an IRA in the first place. Starting salaries haven't budged much in 30 years and you’re probably already strained by student loan and credit card debt. You say, “If the market's going down, why put in my $100 I can barely afford only to see it turn into $70 next week?” Well, because you'll still own what you own—shares—which will go up in value when the market goes up. Buy low, sell much much later... And educate yourself! You’re in the best shape of all. Your preferred money-mix: At least 80% in the stock market; diversified across index funds and sectors; the rest in bonds, T-bills and/or money markets.

30's & 40's: You rode the boom but are now seeing those gains disappear. But just as with 20-somethings, you have more than 20 years to ride through this storm as well as several others before you retire. The trick now is balancing bigger contributions along with the other demands on your money—it's easy to lose sight of long-term investing goals and strategies when you have to split your income between still paying off debt, keeping up with a sinking mortgage, planning for your kid's college costs and possibly helping out aging parents. But if you've got 10 plus years of investing in your IRA down already and you can't stomach this dip, slowly move some allocation to another sector or a broader fund. And if you're shaken sick, consider bringing more money into your 'safety' investments such as another 10% going to T-bills or money markets. But if you started investing later, say in your 30's, you have some catching up to do. Know that when you buy for safety, you lose the possibility of reward through risk. Do the math—20+ years until retirement means keep in the game. Your preferred money-mix: At least 70% in the market; diversified; the rest locked into quasi-cash (bonds, T-bills, money markets).

50's to 65: Pulling all your money out of the market during a slump isn't a good idea—even at 65 you don't need all your retirement right away (let's say you hope to live to 85 or so—that's 20 years to go). But watching the decades in the market you've already banked go bye-bye, seemingly overnight, can be heartbreaking and lead you to want to press your own 'exit' button. Resist. No big moves yet—remember, assess your long-term strategy and make small shifts in your portfolio to tip the balances toward protecting your dollars by 60. Trying to time the market, either by pulling out before it hits bottom or locking profits by pulling out when it goes back up, can be a losing game. No one can call the bottom or the height. Try your best to make adjustments in your allocation based on your time frame. Ten years to go? You've got some time to profit from the upswing. Only a year or two left? Protect what you've got but keep at least 20% in the market to benefit in your later years. Your preferred money-mix: Shift from 60% in the market toward 50% or less once 65 is near.

Post-65: No one wants to retire during a downturn. But small adjustments you make to your day-to-day spending and saving can at least partially close the gap between what you had a year ago and what you have left today. Hold off on IRA withdrawals if possible—let them sit and stew (and hopefully grow) for as long as possible before you're forced to withdraw at 70 1/2. Cutting your day-to-day living expenses can make a difference of thousands a year - heading off your losses in the market and in your income. And don't count out working longer, even just part-time. Watch out for taxes though—you want to protect your Social Security payments. Your preferred money-mix: Keep your toes in; 20% in the market, the rest protected with T-bills, bonds, and money markets.