The new deadline means "we're going to see some good activity coming out of the spring," said Pat Lashinsky, chief executive of online real estate brokerage ZipRealty Inc.
But the government support can't last forever. For example, the Federal Reserve is likely to curtail its effort to push down mortgage rates next year. If rates then rise too high, it would make home purchases less affordable and dampen housing demand.
"When we do kick those crutches out from under the housing market, will it be able to stand on its own?" said Mark Fleming, chief economist with real estate information company First American CoreLogic. "It's really hard to tell."
Another concern is that job losses are pushing once creditworthy homeowners into default. Borrowers with prime, fixed-rate loans accounted for one in three new foreclosures in the second quarter, the Mortgage Bankers Association said last week. Nationwide, a record 14 percent of homeowners with a mortgage were either behind on their payments or in foreclosure.
And in areas where foreclosures have hit hard, housing remains depressed, despite low prices and mortgage rates and the tax credit.
Cleveland real estate agent Colleen Rock notes that the city's economy is still struggling with job losses. Another round of foreclosures could depress prices again.
"Just because we're stabilizing, I can't comfortably tell you we're back to a normal market," said Rock, an agent with Re/Max Crossroads. "It might be another year."