Twenty percent of homeowners are residing in a money pit -- and they don't even know it.

Most homeowners tend to fix up their homes instead of making a dreaded move, and then they spend huge amounts of money before they realize where they stand, says ServiceMagic.com.

So the contractor Web site devised a formula for homeowners to determine if their home's repair costs are going overboard. The national survey identified consumer sentiment about annual home expenses.

"In this changing market, it is crucial for consumers to understand the value of their home in order to know if they should sell, or keep moving forward with extensive repairs," said Craig Smith, ServiceMagic CEO.

The survey results indicate that homeowners spend, on average, one percent of their home's value on repairs each year.

Here are three categories you need to avoid:

Money pit: Consistently spending more than 2 percent of a home's value on annual repairs establishes the house as a money pit.

"Everyone's going to have a bad year when the furnace goes out and the roof needs to be repaired," David Lupberger, a former remodeling contractor and now an official for ServiceMagic. "But when things keep happening, at some point, you have to stop what you're doing, take a step back and objectively ask yourself -- is this worth it?

"People develop attachments to their homes, so giving up on one can be extremely hard to do emotionally," he said.

Sinkhole: If annual repair costs total between 1.6 and 2 percent of a home's value, the residence sits in the "sinkhole" category, a significant warning sign for homeowners.

"In a strong housing market, there are cases in which putting money into a 'sinkhole' might eventually pay off," said Lupberger. "However, in today's world, throwing tons of cash at it could be a slippery slope leading into an abyss."

Drain: Homeowners could be living in a "drain" if they consistently spend 1 to 1.5 percent of their home's value on home repairs.

"Although it's barely above the average in our survey, owning a 'drain' can become tiresome," Lupberger said. "However, many normal expenditures that come with homeownership are likely to land someone in this category."

Forty-four percent of respondents said they found something wrong with the house only after they moved in that the previous owner failed to disclose to them.

The survey asked 300 respondents what they spent on repairs in the first 12 months of homeownership, and in which categories. Of those who indicated they'd had to spend money for a repair, the average costs were:

Flooring, $1,457.

Roofing,$1,376.

Heating/air conditioning, $1,238.

Appliances,$846.

Wall repair/interior paint, $695.

Plumbing, $685.

Siding/exterior paint, $561.

Electrical, $516.

Foundation/structural repair,$488.

How long did it take before couples shopping for a home to realize they had found the right residence? Seventy percent of women made up their mind the day they walked into the house, versus 62 percent of men, according to a new survey.

"Many agents are seeing a rush of first-time homebuyers looking to make a purchase by Nov. 30 to receive the tax credit, meaning in most cases, they must have a contract by about Sept. 30," said Diann Patton, an official for Coldwell Banker Real Estate, which commissioned the survey.

Fifty-five percent of women find it more important for their home to be closer to their extended family than to their job, compared to 37 percent of men.

When asked who "wears the pants" in the relationship (pertaining to major financial decisions, such as purchasing a home), almost 70 percent of respondents said it's mutual.

When the respondents were asked how they would use an extra 12-by-12-foot room if it could be anything they wanted, men and women agreed on the top three most popular, and practical responses: bedroom (25 percent), office/study (15 percent) or family room/den (11 percent).

However, men really do want a "man cave." Out of the 8 percent who indicated they would turn that spare room into an entertainment center, four times as many men as women said they would use the extra space for recreation/entertainment.