I honestly believe that houses have feelings.

For example, they know when they are being sold because they start acting up in unprecedented ways.

You want examples?

Neighbors sold a house they had lived in for 12 problem-free years. The morning the house went on the market, a big crack appeared in the third-floor bathroom wall.

Another neighbor never had flooding in the basement until the day before the new owner settled on the house. For 35 years nothing, and then, when it was most inconvenient, water down below.

The gas meter in my old house in Philadelphia was in perfect working order until I put the house on the market. A week before settlement, the meter began leaking gas and had to be replaced.

Usually, the house reacts more subtly than with a gas explosion or a flood: An inspection uncovers years of termite damage that isn't serious enough to have caused your floor to collapse; the home inspector finds faulty electrical wiring that hasn't yet caused a fire; a toilet appears to have worked itself loose without pouring water into the room below.

Statistics compiled by HouseMaster, a home-inspection company franchiser in Bound Brook, N.J., show that two of every five resale houses that go on the market have at least one serious defect.

How do you avoid those situations? Regular maintenance is the only answer. And it applies equally to new construction and older houses.

I've decided that we should maintain our houses as if we were planning to sell them tomorrow in a bad real estate market. Even in bad markets, a well-maintained, properly priced house will sell faster than the rest.

At a seminar last year at the National Association of Realtors convention in Anaheim, Calif., Ron Passaro of Bethel, Conn., one of the founders of the American Society of Home Inspectors, had an interesting idea.

He suggested that homeowners have their houses inspected before they put them up for sale.

That's a good idea, of course, especially if you've owned your house for a number of years--before the advent of the home inspection industry.

A home inspection costs $250 to $500. The inspector will probably tell you things you may not want to know or things you know already and close your eyes to.

It also will help you accurately fill out seller disclosure forms now required by some states.

If you've owned your house for the last decade or so, you probably had a home inspection before you bought it. You may even have kept the report, so check to see what the inspector had to say and what you've done about it.

Unless it was "fix the hole in the roof above the room where you watch television," you've probably done nothing.

When the inspector handed me my report in July 1987, I tallied up the cost of his recommendations, and it came to $19,000. Although I've spent much more than that in almost 12 years, most of what he found has yet to be a problem.

That's not saying he was wrong. It just means that no one can spend a couple of hours in unfamiliar surroundings and find every fault.

"Even the most thorough termite inspection can't uncover infestation or damage that is inaccessible," said Noelle Barbone, office manager of Weichert Realtors in West Chester, Pa. "A lot of it is discovered when buyers begin removing paneling and drywall from basement recreation rooms, for example."

The termite inspection of my house, done by a separate inspector, uncovered nothing, and I've uncovered none of the critters since then.

The general home inspector, however, didn't get up on the roof, so he didn't see the two missing shingles. He didn't know that someone had mortised a rotting beam with a pressure-treated beam in the porch roof, because to have seen it he would have had to trim a tree, then poke the fascia with an awl.

And how could he have known that the ancient furnace needed a new burner because the old one spewed oil every time the heater clicked on? Someone had carefully closed the valve from the oil tank, so the furnace couldn't be tested.

It was July. Who cared?

"If a house is vacant, and the inspector flushes a toilet once, a plumbing problem might not be apparent," said Christopher J. Artur of Artur Realty in Philadelphia. "The new homeowner may not find the problem till he or she flushes the toilet 49 more times.

"There are no certainties," he said. "In the summer, for example, there may be no evidence of a problem that exists only in winter."

You need to live in a house for a while before you are absolutely sure how it works. Only then can you identify many of the problems, and try to correct them.

Sometimes you stumble on problems you didn't know you had.

Friends of mine redid their kitchen. They decided to replace the old plaster walls. When they broke open the plaster, they found mold growing on the inside surface of the exterior stone walls. They hired a stone mason, who cleaned and repointed the stone and then applied a coating of waterproofing.

Once the work was done and the interior walls were finished, the air inside the house became noticeably cleaner and fresher. My friends felt better physically, and found breathing easier.

So what you need to do is identify the problems and then develop a plan of action, based on your financial situation or, if you do these things yourself, on your schedule.

If, for example, you painted your house a couple of years ago, check the condition of the surfaces. Places where the paint is wearing a little heavily may mask moisture problems that need to be addressed.

Fix the problems now, so when you go to sell the house, you won't be punished for letting things ride.