Buy in haste, repent - and repair - at leisure. But what's a buyer to do? If you take your time, you risk being repeatedly pipped to the post by cash-in-hand speed freaks. If you join the free-for-all, you make the most important purchase of your life in a state of hysteria. Robert Liebman tries to find a viable point in-between.

As desirable residences go, Teresa Hartley's flat, with garden, pond and waterfall sounds extremely "des res" - except that the pond was under her living room floor and the waterfall cascaded down her conservatory walls. And she can consider herself lucky.

Ms Hartley exchanged contracts on her west London flat last spring, while builders were still converting it. The developer's plans called for carpets on all floors, but she intended to refurbish the conservatory and move the living room radiator, so she persuaded him to leave the floors bare.

When Ms Hartley's heating engineer lifted the floorboards to move the radiator, he noticed a pool of water with a diameter of about three feet beneath a still-leaking pipe. The leak occurred at the new section of pipe which diverts the mains water to the two new flats above.

Ms Hartley's engineer fixed the leak easily and inexpensively. End of story, yet that it was discovered by chance. If it hadn't been detected, a horror story might have been in the making. A worsening leak which needed fixing after Ms Hartley put down her new carpets would have been costly, messy and disruptive. More seriously for all three flat owners, who collectively own the freehold, the leak could have caused subsidence. And none of the flat owners could have sued the developer.

How do nasty things happen to such nice people?

Ms Hartley has bought and sold her share of properties over the past 25 years, but her dilemma befalls experienced and first-time buyers alike. It is inherent in the intense pressure of a boom market when every half- decent property attracts many aggressively competing buyers. Even in calmer markets, buyers tend to feel intense pressure when they finally, strongly want a particular property.

An empty-nester, Ms Hartley sold her large home two years ago and bided her time as a renter. She was confident that, as a cash buyer, she would buy from a position of strength, not weakness. But when prices surged in early 1997, it quickly became evident that the longer she waited, the more she would have to pay - and the less property she would get for her money.

Spurred to sudden action, she quickly found several acceptable flats, but each was snapped up by buyers making instant offers and seemingly instantaneous exchanges of contracts. When she then found the conversion she ultimately bought, she pounced. The developer, exploiting widespread buyer desperation, inserted a clause in the lease absolving himself of responsibility for any defective workmanship. "My solicitor advised me not to sign. 'No one puts this in a lease,' he said."

She signed. A local estate agent affirmed the developer's good reputation, and her surveyor deemed the building work satisfactory. "By this point I was desperate."

Her first rainy day revealed that her conservatory flashing was a curate's egg - it kept out half the water. The half that entered did so through more than 20 points of entry, and water coursed down the width of the entire wall. The culprit was leading that looked like lead but was really plastic.

Other minor flaws were readily dispatched by her trusty handyman, and she soon made peace with her property. "In a different town, I really could have come a cropper. I gambled, but I knew the area very well. I decided it was worth taking a risk. If I hadn't bought this flat, I would not have bought anything. My bottom line is needs must. I don't think I acted wisely. But I don't think I'll have difficulty selling."

She also acknowledges that if the builder has installed carpets, she would not have bothered lifting them to move the radiator. With the leak going undetected, the outcome easily might have been decidedly less pleasant.

Most solicitors and estate agents advise buyers to be deliberate and cautious. Haste is too risky, say the solicitors, while estate agents say another acceptable property will come your way - eventually.

Some buyers can afford the risks, which are emotional as well as financial. Joanna Haydon-Knowell bought a house that needed massive internal work and was sinking into the ground. She arranged a mortgage, a survey and a contract within days, but Ms Haydon-Knowell, who owns Muswell Hill estate agency J H-K, knows which buttons to press.

"Obtain a mortgage offer before you start viewing," she advises. "Do it before you enter the estate agency. Until you do see a mortgage advisor, you don't know how much you can really spend. Buyers tell me they can 'probably' spend such and such. But you must know the most that they will lend you exactly, to the penny."

Buyers must also allow for speed bumps. "Some solicitors really push, but generally they are not urgent," says Tony Seeney, of estate agency David Conway in South Harrow. "In the 1980s there was a lot of panic buying, and since then a lot of surveyors have caught a cold and are now very cautious."

Mr Seeney's colleague Tim Robertson occasionally encounters buyers who put their property back on the market within a day or two of moving in. "Buyer's remorse," as he calls it, can occur when a buyer discovers that the property or neighbourhood is noisy or untidy. He believes that some remorseful buyers were propelled to buy primarily because "they have a mortgage offer and want to use it before it expires."

Conveyancing hitches are usually frustrating and unwelcome, but buyers can use these slowdowns to conduct further research and reassess their position. Usually a slow solicitor or fastidious surveyor entails only delay. No-fault clauses in leases, on the other hand, are "STOP" signs in disguise. Buyers ignore them at their peril.

J H-K Estate Agent, 338 Muswell Hill Broadway, Muswell Hill, London N10, 181 883 5485; David Conway Estate Agent, 269 Northolt Road, South Harrow, Middlesex, HA2, 0181 4225222; Royal Institution of Chartered Surveyors (RICS), 12 Great George Street, Parliament Square, London SW1P 3AD, 0171 2227000; Council of Mortgage Lenders, 3 Savile Row, London W1X 1AF, 0171 4370655.