But Eric Messer is a contractor; his family, after 12 years in this 4,000-square-foot home abandoned long ago by a bankrupt developer, are overdue for a dream change. Although the house's transformation took more than a decade -- and his wife and two sons put up with various stages of construction for much of that time -- the Messers are ready to move into another home-in-progress.

Their destination awaits them across town. It is a splanch -- a boxy 2,200-square-foot amalgam of split-level and ranch design that was contemporary when Eisenhower was president.

Despite a rickety carport in front, a healthy crop of moss on the tar-coated roof, and a heating system well beyond its useful life, the family is eager to move inside. The house has great potential -- which is all they require.

''The bones are there, and we'll make it desirable,'' said Mr. Messer, owner of Sunrise Building and Remodeling in Briarcliff Manor.

An adventurous home improvement spirit like his is presumably what the rest of us search for when hiring someone to renovate our homes. We want a builder whose own home provides concrete evidence of expertise, talent and taste -- even if we never actually see the place.

Perhaps that is why builders can be fanatical about owning the biggest, most up-to-date homes they can afford. Or perhaps their quest has more to do with the significant tax break available on their resale profit, for a primary residence they have been living in.

In Westchester County's superheated real estate market, resale values can be substantial. The county has had the highest residential home sales prices in New York State for years; in May, the median price of a single-family home was $700,500, according to the New York State Association of Realtors. That number, still on the increase, will probably set a record for the second quarter of this year, according to P. Gilbert Mercurio, chief executive of the Westchester County Board of Realtors.

''The activity has shifted from new residential building to renovations, fueled by low interest rates and the tremendous equity people have in their homes,'' said Albert A. Annunziata, executive director of the Builders Institute, a trade organization based in Armonk.

Even beyond the investment value their own homes offer, many builders view them as flagships to impress high-end clients or to feature on the company Web site.

They tend to equip the homes with a hodgepodge of the latest gadgetry, usually bought from repeat suppliers at a steep discount. They may also favor material thrown away by other homeowners or left over from job sites.

All these factors can sometimes produce a house not thoroughly welcomed by neighbors -- who may have less eclectic ideas about what constitutes good taste.

EVEN a builder has his own budget and limitations,'' said Barry L. Cohen, a developer. ''The money is not endless.'' Nevertheless Mr. Cohen recently finished building his family a 6,000-square-foot house on five acres at the end of a 900-foot driveway in Pound Ridge.

Mr. Cohen, who has owned J.B.C. Development since 1997, estimates that he spent more than $1 million on his five-bedroom, five-bath, two-half-bath, shingle-style Colonial. It had to be very large, he explained, because when he resells it, he wants to ask more than $2.5 million, and any home at that price has to have at least 5,500 square feet. He also said buyers of such homes expect at least one bathroom for every bedroom.

In addition to features typically associated with this size house, like granite-topped kitchen counters, fixtures with satin-nickel finishes and a walk-in steam shower seemingly large enough to fit a family of five, there are extras like a six-zone heating system, total home wiring for alarm, heat and stereo system, bundled network cabling, touch-pad lighting and heated cobblestone floors.

(One luxurious element that he wouldn't choose again: the cedar shingles on the exterior. They have proven extremely popular with Pound Ridge's woodpecker population. Next time, he plans to use hardier synthetic shingles, made to look like wood.)

He had intended to use the home as a sales tool -- one that he could show to potential buyers to demonstrate the quality of his work.

''But it's a Catch-22,'' he said, ''because you want to impress people but it's a privacy issue because I don't want to bring strangers into my house like a revolving door.''

Nor did he really want to show the house to customers tackling more modest renovations, because its features and amenities were out of their price range.

For his part, Mr. Messer has solved the privacy problem, as well as the embarrassment of having a nicer home than some of his clients, by anonymously featuring select parts of the house on his Web site, sunrisebuilding.com. He included three of his bathrooms and his kitchen, although they aren't labeled as such.

The desire for more expensive materials comes naturally in the business, he said: ''If I put granite countertops in 20 kitchens, why would I want to come home to Formica tops?'' Moreover he finds it useful to install all the latest plumbing fixtures, hardware and cabinetry in his own home, ''because I get to test out the products'' before using them on a customer's house.

This is music to Mrs. Messer's ears -- although she knows she is in for another wait before getting to try out contraptions like a kitchen drawer that is actually a small dishwasher or another that is a minirefrigerator. The canon of Newer is Better is religiously adhered to by builders and contractors -- even those who have been in the business for decades.

''It is absolutely essential that I live in a house of my own design, preferably a new one,'' said Arnold J. Foster, 87, who has built hundreds of homes in the Boston area and, more recently, about a half-dozen in Westchester.

His current home, 5,500 square feet of gabled stone and stucco in Yonkers, was built on the site of a much smaller 1950's Colonial he tore down in 1998. The new place has a two-story central foyer, five bedrooms and five bathrooms.

Such homes are rewarding to builders and contractors financially as well as personally. Acutely aware of the investment potential, some call it the best opportunity to build wealth in America. If a contractor sells a primary residence in which he has lived for two out of five years, a profit of up to $500,000 is tax free, according to Leonard M. Sander, a Tarrytown accountant. If he renovates during that time, profits can be substantial.

This tax exclusion was clearly important to the Messers, who sold their home for $1.14 million. ''We don't know the stock market,'' Mr. Messer said, ''but we do know how to remodel houses.''

Another source of savings: Supplies can often be bought at a discount, and odds and ends left over from other jobs can be used. Builders make a point of telling suppliers that the merchandise is for their own home, with a view to getting a discount.

''I would expect them to do something for me when I'm a loyal customer,'' Mr. Cohen said, adding that he had probably bought much of what he needed for his own home closer to cost than if he had been building a house for others.

Builders are adept at finding unwanted treasures in the trash, or in the surplus pile. Mr. Messer installed a door in his home that had been thrown out by a client in Irvington, and he sometimes culls excess Italian tiles elsewhere. Mr. Cohen used discarded barn siding for a built-in wall unit that now surrounds a large plasma television set. He also saved an 1800's outhouse from a client's property; he uses it as a storage shed next to his driveway.

WHAT, generally, are the neighbors' reactions to contractor dream homes? Sometimes, as in Mr. Foster's case in Yonkers, they are less than delighted.

After he had razed what he called ''a reject home'' in Lawrence Park West, he built one nearly three times the size in its place. Unsurprisingly, the home does not quite blend into its environment of traditional Tudors and center-hall Colonials.

''I don't particularly like what it looks like, and I don't think it conforms to the neighborhood as well as it could,'' said a neighbor, who refused to give her name because, she said, she didn't want to stir up bad feelings.

Mr. Foster's response to this anonymous criticism: ''I think that's a case of sour grapes, because my house is a little larger.''

On the other hand, Terrence A. Price's Yonkers neighbors couldn't be happier with his work. Mr. Price bought a run-down 6,000-square-foot Victorian built in 1892 and has spent 11 years renovating the place, which he called ''my showroom.''

A neighbor, Michael Ingram, was enthusiastic in his compliments, saying Mr. Price's efforts had increased his own property values. The house, he said, ''is beautiful, it's in impeccable taste, it's creative.''

Every room in the house is painted a different color; there are Palladian windows with leaded glass, as well as 10 fireplaces, and Hudson River views from the redone porch and newly terraced backyard. There is also a pool with a templelike pool house that Mr. Price designed and built.

Mr. Price's partner, Milton A. Buras, described him as the kind of person who can ''walk into a space and know what it should look like.''

As an example, Mr. Buras remembered an occasion several years ago, when ''I wanted to have lunch outside, but we didn't have a table.

''He said, 'If you make the lunch, I'll make the table.'''

With legs and braces made from a nearby birch tree and leftover boards for the top, the table was ready before the hamburgers.

Whatever neighbors may think about the new homes, though, there is no question that many appreciate having a builder nearby.

Mr. Cohen, for example, lives near three neighbors on a private road that desperately needed repaving. He recently found an excavator and a paving company at reduced rates -- a favor for which the neighbors were grateful, because they all had to share the cost.

Mr. Cohen's wife, Jamie, says she appreciates living in a house with the man who built it. ''He knows every wire in the house,'' she said, ''and if there's a leak, he knows exactly where it's coming from.''

Mrs. Messer, making a related point, said friends ''call here when they have an emergency, because their husbands can't fix anything.'' She added that she likes being married to a man who ''really knows how to do everything and how to plan it.''

There are of course the contractors who are too busy to be meticulous about their own home renovations, she added, and they often infuriate their spouses.

''Wives can't stand it if they are in perpetual construction, when their husbands squeeze in the work on nights and weekends,'' she said, especially if the family ends up with no kitchen or bathroom for four years.

''I know many contractors who live in half-built houses,'' she said, ''and each project goes on forever. It causes real marital strife if not planned properly.''

THAT was not a problem for George S. Braverman, a builder who decided to surprise his wife, Claire, by renovating the bathroom in their 10-year-old house during a week when she was away last fall.

Mr. Braverman, owner of Nantucket Home Builders, hid all the materials in a shed on the couple's White Plains property, as well as at a house he was building. He made sure that his plumber and carpenter were hiding around the corner on the Saturday morning that his wife left.

''The code word for them to show up was 'The chicken has flown the coop,''' Mr. Braverman recalled. Working fast, he and his crew discovered ''how many guys you can get into a bathroom.'' It's about 10, he said.

This kind of busman's holiday is not for every builder. Norm P. Jen, who has lived in his 2,400-square-foot house in Chappaqua for 12 years, has completed just two modest renovation projects on it. An owner of the Jenesis Building Corporation in Chappaqua along with his two brothers, Mr. Jen has three children, all of whom are competitive swimmers.

''When I come home, the last thing I contemplate doing is ripping my own house apart,'' he said, adding that his house is already ''nice and comfortable, and everything works.''

Mr. Jen spends his time attending swim meets -- at least three a week.

Photos: Eric Messer turned his early-90's contemporary in Briarcliff Manor, top, into the family dream home, but now it's time for a new dream, so the Messers are moving across town to a ''splanch,'' below, the it-house of the Eisenhower era. As Mr. Messer sees it, ''The bones are there, and we'll make it desirable.'' Arnold Foster's 5,500-square-foot stucco and stone home in Yonkers, left, a version of today's trophy house, replaced a much smaller 1950's Colonial. (Photographs by Chris Maynard for The New York Times)(pg. 1); The transparent drawer fronts, far left, in the Messer house in Briarcliff Manor and the walk-in pantry in the Price house in Yonkers, right, are the kinds of features that contractors frequently include when designing their own homes. (Photographs by Chris Maynard for The New York Times); A staircase in the 1892 Yonkers home, above left, of Terrence A. Price. With its Hudson River views, below, and the templelike pool house Mr. Price designed and built, neighbors say the house has increased the value of theirs. One of five baths, above right, in the Pound Ridge home of Barry L. Cohen. For resale purposes, he included a bath for each bedroom. And as a nod to history, he salvaged an 1800's outhouse, right, from another site. It is used as a tool shed. The dining room, left, in the Yonkers home of Arnold Foster, who considers it ''absolutely essential that I live in a house of my own design.'' (pg. 6)