Wealth isn't determined by any fixed amount, but you certainly think it is.

Despite financial advisors' insistence that wealth should be a more flexible ideal, there's still a reluctance to see it as anything but a figure in a ledger. According to a survey from Charles Schwab, there are some investors who have a more abstract view of wealth. Some say wealth is enjoying life's experiences (24%); others view it as stress-free living and peace of mind. Even having loving relationships with friends and family (12%) can be considered "wealth."

That said, having lots of money (27%) and affording anything you want (22%) still factor heavily into how the average American assesses wealth. When asked to express how much is required to be considered "wealthy" in America, survey respondents say it's an average of $2.4 million, or nearly 30 times the actual median net worth of U.S. households, according to the U.S. Census Bureau.

Though 65% may say that wealth is more about having good physical health than having lots of money (35%) and 58% say that wealth is about having gratitude vs. having money (42%), their actions still indicate that they view any non-financial "wealth" as a consolation prize.

"Wealth is often thought of as a lofty, unattainable number that doesn't apply to most of us, but that's an old-fashioned notion that needs to be retired," says Terri Kallsen, executive vice president and head of Schwab Investor Services. "It doesn't matter whether you have a lot or a little—what matters is that you think about the money you have as your wealth, and that you pay attention to it. Being engaged is the only way to reach your personal goals."

Yet even the wealthy aren't certain of what constitutes wealth. In a survey of 2,215 U.S. investors with more than $1 million, UBS found that three-quarters of millionaires (77%) grew up middle class or below. Working their way up the socioeconomic ranks was a conscious aim, as 61% aspired to become millionaires and 65% felt it was an important milestone to reach the $1 million mark.

While nearly three-quarters of millionaires (74%) surveyed feel like they have "made it" and 44% said hard work was the single most important factor in becoming a millionaire, there's clearly greater satisfaction with increased wealth. Of those surveyed, 73% of those with $1 milion to $2 million reported being "highly satisfied" with their life, compared with 85% of those with $5 million or more. While 37% of those with $1 million to $5 million said their wealth allows them to live a fairly luxurious lifestyle, 62% of those with $5 million or more said the same.

Roughly 58% of all millionaires report feeling increased expectations for their standard of living over the last ten years. Among working millionaires with children at home, 52% feel like they are stuck on a treadmill, unable to get off without sacrificing their family's lifestyle.

"The majority of millionaires say they have worked hard to earn their wealth and appreciate the lifestyle it affords them and their families," says Paula Polito, Client Strategy Officer, UBS Wealth Management Americas. "But enough never seems to be enough—even the wealthiest continue on the treadmill to achieve a better life."

Millionaires' wealth hasn't done much to assuage their fears either. Half of those with $1 million to $5 million are afraid that one major setback (job loss, market crash) would have a significant impact on their lifestyle. Even 34% of those with $5 million or more feel the same. Give those same millionaires kids, and suddenly 63% feel that one major setback would have a significant impact on their lifestyle.

Maintaining that lifestyle comes at a cost, as 64% of millionaires report that they have had to give up family time to achieve their dreams. Most millionaires (68%) admit to having regrets, most commonly around making mistakes in a relationship with their spouse or family and not spending more time with family. They worry that their children will grow up without the right values, with two in three (67%) already feel that their children take things for granted and more than half (53%) are at least somewhat worried that their children act entitled. Millionaire parents expressed concern that their children do not understand the value of money (65%), lack motivation (54%), have unrealistic expectations (54%) and will embark on an unstable career path (50%).

So how do you strike a balance? Well, having a written plan helps. Charles Schwab found that 54% of those with a written plan have increased their 401(k) contribution in the last year, compared to those without a plan. The folks thinking ahead are also more likely to rebalance their 401(k) portfolio (50% to 24%), stick to a monthly savings goal (40% to 19%), have an emergency fund (45% to 26%) and be aware of fees in their brokerage account (83% to 67).

According to Schwab, more than a third of Millennials (34% of those ages 18 to 36) say they have a written financial plan compared Generation X (37 to 52, 21%) and Baby Boomers (53 to 71, 18%). Nearly three-quarters (72%) of Millennials developed their written financial plans with professional help, and 91% of them review or update their financial plans at least annually. Among older Millennials in their 30s, nearly 57% say their financial health is better than it was five years ago and nearly half (47%) say they have a household budget compared to those in their 20s (35%) who admit they do not.

"The positive behavior changes we're seeing among older millennials are encouraging. With their focus on planning, they're already poised for success," says Kallsen. "Much like the generations before them, millennials will advance in their careers, start families, and accumulate wealth - all factors that will lead to even more financial engagement."