But it goes both ways: There are people who have lots of money, and yet they don't spend very much of it. Fenton says some of the findings in a book called "The Millionaire Next Door," written in the late 1990s by Thomas J. Stanley and William D. Danko, remain true today, such as the notion that the average millionaire will spend about $12 on a haircut while those with far less money spend about $20, or the fact that while some millionaires drive Mercedes-Benzes and Saabs, most drive very basic cars. Many of those interviewed for the book said they hadn't bought a new suit in 20 years.

Fenton says it saddens him when he has clients who have so much and spend so little. He'll tell them to travel the world. The phenomenon is more common with people who have built their own manufacturing business, perhaps in a blue-collar industry. Perhaps they're the child of an immigrant, and they built a business over 40 or 50 years, and now it's worth $100 million, yet they've never taken home a salary of more than $60,000. They'll have $50 million in net worth, they drive a Ford pickup truck, and the most lavish thing they've done is take a trip to Disneyland.

"And then the kids inherit it. And so, sadly, this person has been pinching pennies for 30 or 40 years, and the money is only going to end up in a drug rehab program for their kids," Fenton says.

It's great to save money, Fenton says, but when you're a billionaire and you're mowing your own lawn and changing your own oil, you have to ask yourself, "What kind of quality of life do I have?"

There's an old saying, "Do you die with a million dollars or a million memories?" The lucky ones manage to have both.