Our tough economy is forcing people to resort to tough choices. According to a recent Time poll, 27% of Americans have taken money out of their retirement savings to cover some of their current expenses. Unfortunately, that scary move can do more long-term harm than short-term good.

The longer you leave your money alone to grow, the more powerful your compounded returns become. Check out what time, patience, and an average 10% return can do to a steady series of $10,000 annual investments:

After 1 year

$11,000

After 5 years

$67,000

After 10 years

$175,000

After 15 years

$349,000

After 20 years

$630,000

After 25 years

$1.1 million

After 30 years

$1.8 million

You don't necessarily need to be a financial wizard to score those kinds of returns. Broad-market index funds, which include big companies such as ExxonMobil (NYSE:XOM) and Schering-Plough (NYSE:SGP), have thus far averaged 10% a year over the long haul. (In fairness, they could return more or less over your given investing time frame.)

You could even juice up your basic returns by adding a handful of well-chosen individual stocks to your fund foundation. The following stocks have done extraordinarily well in the past five years, while maintaining reasonable valuations and solid returns on equity:

Company

P/E

ROE

5-year avg. annual gain

PotashCorp (NYSE:POT)

11

58%

53%

McDonald's (NYSE:MCD)

15

32%

20%

Schwab (NASDAQ:SCHW)

18

29%

14%

BHPBilliton (NYSE:BHP)

7

40%

28%

Lockheed Martin (NYSE:LMT)

11

52%

13%

Data: Yahoo! Finance.

But remember, those impressive gains can quickly fizzle if you start taking money out of your retirement accounts.

Suppose you take out $10,000 this year, 20 years from retirement, and you also fail to make your usual $10,000 investment. Good intentions to the contrary, you probably won't put in $20,000 next year to compensate. So you'll lose what the $10,000 you withdrew would have grown to in 20 years: a little more than $67,000. And you lose that additional $10,000 you would have invested, too: another $67,000 loss. You might pay some bills in the here and now, but your retirement could eventually end up more than $150,000 poorer. Is that worth it?

People make lots of mistakes with their retirements. Steer clear of them if you can, but if you've already made a few, take heart -- you can still salvage your retirement. A free 30-day trial to our Rule Your Retirement can give you an excellent head start.

Further Foolish tips for retirement:

Longtime Fool contributor Selena Maranjian does not own shares of any companies mentioned in this article. Charles Schwab is a Motley Fool Stock Advisor pick. Try our investing newsletters free for 30 days. The Motley Fool is Fools writing for Fools .