When the recession began, Americans began to save more of their money, prompting predictions that their financial habits might be changing permanently.

But the surge has not been sustained. In September, the nation’s savings rate dropped for the third consecutive month, the Commerce Department said Friday. It is now at 3.6 percent of personal disposable income, its lowest level since the month the recession began.

The latest decline raises the question of whether consumers are returning to their old spendthrift habits or were temporarily relaxing budget restrictions to make long-awaited purchases.

Real personal after-tax income declined in September, just as it did in July and August. Even so, consumers spent more, for an increase of 0.6 percent in September.