FROM her flagstone patio, homemaker Trish Thoman tells why this booming metropolis is the best place her family has ever lived: big-city amenities at a small-town cost.
Miles to the north, in the driveway of her older home, Doris Straithern explains why she wants to move her family back to Minnesota: smog, congestion, crime. ''My kids are getting jumped after school, and the air's beginning to stink,'' she says.
The two points of view are increasingly echoing across the desert here, where one of America's fastest-growing cities is spreading out amid the cactus at the rate of an acre an hour.
Once merely a sun-dappled retirement center, Phoenix has grown into the country's seventh-largest city. Yet a region that has never shied away from growth is asking the ''Double Jeopardy'' question: When is enough, enough?
''Until just recently, the issue of population growth has been perceived as nothing but absolute good,'' says Jay Butler, Arizona Real Estate Center director at the University of Arizona. ''Now people are growing very concerned.''
To accommodate the numbers, developers carved out 9,000 acres of the surrounding Sonoran desert last year alone, with no letup in sight.
National economists concur that Phoenix will remain one of the nation's top growth spots for at least another decade, partly because its sprawling flatness has no natural, geologic barriers. At 9,000 square miles, Maricopa County could hold the world's 10 largest cities. In 25 years, its urban area is expected to be another 65 percent larger than it is now - 340 more square miles.
The bad news is that even those who moved in just two years ago with promises of clear skies and untrammeled landscapes are beginning to feel cramped by the growth.
''When I moved here in 1993, I had a pristine view of saguaro-topped foothills,'' says a woman outside a SuperCuts store at the Silver Creek Plaza in Ahwatukee. ''Now I look at a mini-mall full of yogurt shops, karate-trainers, and pedicure offices.''
The good news is that business is booming. Arizona is projected to have the third-highest growth in the country in gross state product from 1992 to 2000, and fourth highest for 1983 to 2000.
Along with the lower cost of living and the aesthetic allure of the desert, jobs continue to drive the influx. The construction industry alone is expanding so rapidly that firms are bidding for one another's electricians, pipe fitters, and roofers.
Job growth has accelerated faster than population growth. ''Because the area has become a mecca for new and expanding industries, Phoenix has expanded its position as business center for the Southwest,'' says Andy Grose, president of Westrends, a firm that tracks demographic trends in the West.
Companies come for lower taxes and cheaper labor, an educated population that is younger on average than the country, but that also includes a high number of retirees who want to continue working. A ''right to work'' state, Arizona also has the lowest rate of unionization in the country.
For now, the biggest growth is in information-intensive operations such as credit-card centers, customer service, reservations, technical support, and data centers. Thirty-two such companies have relocated or expanded here in the last 32 months. Certain kinds of manufacturing companies - such as the aerospace computer chip - are also attracted to the low humidity and clear weather.
Phoenix also makes it easy for industry to relocate. ''A key factor when we chose Phoenix over other destinations in the US was how quickly we could get through the regulatory process to build and operate,'' says Mike Edwards at Intel Corp., which is building a $1.3 billion microchip manufacturing plant in Chandler, south of downtown Phoenix.
But because the jobs provided will help bring 600,000 more people to the valley in the next 10 years, city officials increasingly complain about the strain on public services from garbage collection to police and fire protection.
''We can't afford it,'' says deputy city manager Jerry Swanson of Glendale in Maricopa County, who projects his city will expand to 250,000 by 2020 from 162,000 today. The cost of services for that many more people? Some $470 million. Today's developer fees average about $4,500 per house, well short of the $8,000 to $11,000 planners say the city needs to pay for services it provides.
Yet, along with the growing complaints, the term ''managed growth'' is being heard with increased frequency.
''We're never going to be able to stop growth; the test of this city will be whether we can manage it to the liking of both old and new citizens,'' says Phoenix Mayor Skip Rimsza.
He rattles off a list of stop-gap measures that includes increasing fees charged to developers, providing resources to keep up old neighborhoods, stiffer regulations for building design, and clustering communities in ways that preserve natural desert drainage.
To preserve the character of the surrounding desert, the Maricopa Association of Governments has also introduced a ''Desert Spaces Plan.'' Ideas include buying development rights to grazing land and leasing land to keep as open space. The city of Phoenix is also attempting to buy surrounding land to preserve views.
Not every attempt to draw a line in the sand is working, however. A recent City Council plan to slow construction was rejected 7 to 1 in February.
''Politicians here have more self-interest in keeping this a boomtown,'' says Joseph Wilder, director of the University of Arizona, Tucson's Southwest Center. ''I think it has to do with the inferiority they have felt for decades of feeling like they are provincial. Now, they feel like players and they love it.''
If this is to become anything more than ''the geography of nowhere - strip development, suburban sprawl, franchise establishments and ... a loss of meaningful public space,'' Mr. Wilder says, new ideas are needed to revivify the debate beyond the traditional ''tree huggers vs. cement heads.''
One form he offers is the traditional Sonoran architecture still widespread in northern Mexico: high density but low rise buildings with courtyards or patios. ''This model spares the mountain views, makes it cheaper to provide services and public transportation, preserves space and thereby the desert,'' he says. ''It can accommodate everyone's concerns without chewing up the environment in insane ways we can't support.''