Bankrate.com checked into what's worrying people and why, and came up with which groups are winning and which are losing at savings, as well as what's driving them to modify their behavior.

Here's a look at 8 big reasons people are saving more:

8. Other.

While there's no way to know what these "other" reasons are, a surprising number of people chose this category as their reason to cut spending and save, with 16 percent of those aged 18–29, 64 percent of those aged 50–64 and 20 percent of those 65+ picking this option as their response.

No one in the 30–49 age group admitted to this one, though.

7. Frugal/on a budget/no desire to spend money.

Only the oldest respondents cited this combination of reasons to save more, spend less—with 45 percent of those between 50–64 and 34 percent of those 65+ choosing these.

Women made up the majority, at 75 percent, and no one in the younger age groups 18–29 and 30–49 admitted to simple frugality—which highlights what other studies have found: that older women have to function on less money as they age.

6. Less income.

While one percent of respondents cited this, it's probably because saving is tough enough on a regular income. If that income shrinks, it's going to be even tougher. And given that a portion of each age group reported being unemployed—15 percent for the 18–29 crowd, 20 percent for the 30–49 group, 24 percent of the 50–64 group and 41 percent of the 65+ crowd (not those who indicated that they were retired)—or working just part time, that could also account for it.

5. Need to save more.

Overall, this was the big winner, with 36 percent of respondents saying they need to have more money put aside. And it's not surprising, since an earlier Bankrate study found that just 4 in 10 Americans have savings that could cover an unexpected $500 expense.

But it's not just those unexpected expenses; nearly half of all households don't have enough retirement money put aside to keep up their current standard of living in their later years, according to the Center for Retirement Research at Boston College.

4. Worried about job security.

While four percent of respondents indicated that they're concerned about their continued employment status, for them that was enough to boost savings and cut spending. Interestingly, men are more worried about job security, at 67 percent, than women at 33 percent—as are those aged 30–49, 58 percent of whom are concerned about their longevity on the job.

They're also the age group most concerned with having too much debt—a scary prospect: worried about debt and employment at the same time.

3. Worried about the economy.

Ten percent of respondents are concerned enough about the economy to shave their spending. In fact, the Bankrate Financial Security Index fell in October for the second month in a row, to 103.1. While any reading over 100 indicates improved financial security compared with a year ago, the current reading is still the lowest since January.

And although Americans' feelings about their job security, net worth and overall financial situation—three of the five components making up the index—have gone up from where they were 12 months ago, comfort levels with savings have gone down. Debt comfort levels have not changed.

Women, incidentally, are more concerned about the economy than men, at 64 percent compared with 36 percent. And those aged 50–64 are the most concerned age group, at 38 percent, followed by 34 percent of those aged 30–49.

2. Too much debt.

Credit card debt is at an all-time high, Bankrate says, as are student loans. Business Insider says it's now higher than it was just before the 2008 financial crisis hit—and it was at an all-time high then. A Federal Reserve report released in August says that outstanding revolving credit, which includes credit-card debt, rose to $1.02 trillion in June.

And while so far foreclosures haven't challenged the heights they reached in the financial crisis, credit card and auto loan defaults are rising. In the first quarter, the New York Federal Reserve saw a 7.5 percent increase in the share of credit-card balances that were seriously delinquent, or at least 90 days past due.

So it's not surprising that 13 percent of respondents say that that's the reason they've cut back spending.

1. Income hasn't changed.

The lack of pay raises has hit people hard, with 27 percent overall of respondents saying that's why they're stashing more cash. When the needle doesn't move upward on the income meter, that can make it tough to meet all the expenses whose needles are going up—health care expenses chief among them.

So people are doing their best to lower their spending levels to compensate.