The mysteries of 401k savings are little understood by most people, yet they are an important part of personal finance in the USA.

A big question, often asked, is what happens to their 401k savings when they quit working. The reality is, not many people work in the same job for an entire lifetime. When you quit working, you have some options.

First, you can cash out. This is probably not your best option, but it’s your money. You can have the plan send you a check, and you can spend it as you please. Note that you’ll only get a check for 80% of your money in the plan — the other 20% goes directly to the IRS as a down payment on your taxes. They figure you’ll owe them at least that much. If it turns out you owe less, you may get it back as a refund.

Next, you could leave the money in the 401k plan. Your account balance often has to be above $5,000 to do this, but some smaller employers will let you hang around even if you have a smaller balance. Depending on how much you like the plan, this might be a good option. However, you’re leaving your retirement savings in somebody else’s hands — your former employer’s. They decide which investment company handles the money, and they have to sign off on any distributions from the plan. This can make it tough to get anybody to do anything if you ever want to do something with your money – you have to wait for several people to sign off.

Finally, you can roll your savings over to another similar account. If your new job has a 401k or 403b, these might work. Likewise, you could just roll the money into an IRA, where there will be no employer involved at all. By taking the money with you, you keep control over it. The only drawback to this option is that you actually have to take action and make some decisions on what to do with the money.

Of course, you’ll find that tax laws around these accounts change every day. Therefore, you ought to speak with a tax advisor and get some individualized input on what to do before you make any expensive mistakes.

Credit cards are easy, right? You have a credit limit. As long as your balance isn’t as high as your credit limit, you can pay for things with your credit card. When you pay for something with your credit card, you don’t have to pay for it until later. You pay interest on your credit card balance and as long as you don’t go over your credit limit, everything’s fine.

Well, not quite. Here are some of the most frequently asked questions about credit cards — and their answers, of course.

What’s interest?

In a nutshell, interest is money that you pay a lender for the privilege of using HIS money to buy something.

What’s this about “interest rates” and percentages?

The interest rate is a way of determining how much you’re paying for borrowing money on your credit card. It’s stated as a percentage of the outstanding balance on your card, usually as an APR or annual percentage rate. The lower the APR, the less interest you’re paying on the amount you owe.

Okay — so why would anyone choose a credit card with a high interest rate?

Most people don’t CHOOSE to pay a high interest rate. The bank decides what interest rate it will charge you, usually based on how much of a “credit risk” you are. They determine that by looking at your history of paying bills. If you’ve got a history of paying bills on time, then you’ll qualify for lower interest rates. If you haven’t ever had any bills to pay, or if you’ve had trouble paying your bills, that will show in your credit history, too. Since it’s a little riskier to lend you money, banks will charge a higher interest rate.

One other reason that people might actually choose a credit car with a higher interest rate is for the rewards or privileges that come with that card. If the card includes special perks that you want, they may offset the higher interest rate and make it worthwhile.

My card says that I pay interest on the “outstanding balance”. What does that mean?

Your outstanding balance is the amount that you owe altogether on your credit card. Credit card companies generally calculate what’s called an “average daily balance” for each month and base your interest charge on that. If you had a $50 balance from the first of the month to the twentieth, then charged a $400 computer, your interest will be computed on the average between 20 days at $50 and 10 days at $450.

What’s the “minimum payment”? As long as I pay that, I’m fine, right?

The minimum payment is the lowest amount that the credit card issuer will accept toward your balance. It varies from month to month, depending on your balance. Paying JUST the minimum balance may keep your credit card active and keep the credit card company from reporting your account as delinquent, but it will barely make a dent in the amount you owe. Whenever possible, you should pay more than the minimum amount. In fact, it’s best to try to pay off your balance in full each month to avoid paying interest charges.

Last week the S&P500 hit an all-time high, throwing off years of sluggish performance.

To underline that, just compare the S&P with Britain’s FTSE100. Over most of the past seven years, the Footsie has steamed ahead of its U.S. equivalent. In the last five years the UK index has leapt 50 percent compared with 12 percent in American markets. Over the past three years, the S&P500 has returned 30 percent set against 64 in the UK.

Since 2000, the U.S. index has fallen overall by 8 percent compared with a gain of 32 percent by the Footsie.

Peter Seilern of Seilern Investment Management responds, “People talk about the trade deficit which is no worse than many eurozone countries. And if you look at valuations, the S&P500 is trading at about 18 times earnings, which is neither cheap nor expensive. America has a culture of enterprise and some of the best managed companies in the world.”

Cormac Weldon, head of U.S. equities at Threadneedle, says, “There are now sound reasons for investors to reassess their allocation to the U.S. market.”

For the first time in 16 years, U.S. house prices have fallen, raising fears over the economy. This could in turn have a knock-on effect on the rest of the world.

This doesn’t seem to be an isolated incident, as the UK Land Registry is reporting a long-expected fall in the British property market — a 1.1 percentage fall last month, bolstered only by buoyant figures for London.

Standard & Poor’s/Case Shiller Index reports that American values fell 1.4 percent in the first quarter compared with the same period last year. They were also down 0.7 percent on the final quarter of 2006.

The OECD (Organization for Economic Cooperation and Development) warned that the spillover effect could be “more pronounced than generally expected”.