For consumers heavily dependent on credit, the realization is life-altering.

Experts say that even when the current credit crunch eases, the nation may finally have maxed out its reliance on borrowed cash. Today's crisis is a warning sign, they say, that consumers could be facing long-term adjustments in the way they finance their everyday lives.

''I think we're undergoing a fundamental shift from living on borrowed money to one where living within your means, saving and investing for the future, comes back into vogue,'' said Greg McBride, senior analyst at Bankrate.com. ''This entire credit crunch is a wakeup call to anybody who was attempting to borrow their way to prosperity.''

Experts say a prolonged period of tighter credit is ahead.

U.S. consumers will find it much harder to get a credit card, and to carry large balances. Late fees will rise and lines of credit will be reined in. After years of buying homes with interest-only loans, or loans that allowed people to borrow more than the value of the home, substantial payments and downpayments will be required. Interest rates are also likely to rise.

Lenders, far more wary of risk, have tightened standards used to judge potential borrowers. Regulators will be looking over their shoulders.

The changes cap three decades in which U.S. consumers - along with businesses and government - have run up ever-increasing debt. Americans became accustomed to financing purchases large and small with plentiful credit cards, easily approved loans for cars and the latest conveniences, and by siphoning the equity in their homes. Lenders did far more than just make credit plentiful. They aggressively marketed it as a necessity, a way for the smart consumer to leverage themselves into a better lifestyle.

The financial meltdown has made clear the role an increasingly global economy played in facilitating U.S. consumers' borrowing, with banks packaging and selling debt to investors, providing cash to people who once would have been too risky to get a loan.

The expansion of credit has, in many ways, been a good thing. It has allowed many more people to buy homes. At a time when household incomes have stagnated, borrowing has made it possible for many people to afford purchases and cover short-term expenses they might otherwise have had to delay or abandon. That borrowing came at a heavy cost. Americans are more reliant on debt then ever before.

The portion of disposable income that U.S. families devote to debt hit an all-time high in the second half of last year, topping 14 percent, figures from the Federal Reserve show. When other fixed obligations - like car lease payments and homeowner's insurance - are added in, about one of every five household dollars is now claimed by bills.

The credit card industry lobbied heavily in 2005 to tighten bankruptcy laws to make it more difficult for consumers to shed responsibility for paying off debt. The average amount of credit card debt discharged in Chapter 7 bankruptcy filings has tripled, to $61,000 per person, from what it was before the law was passed.