Back in 1979, Roger W. Snyder was considering a job with the Prince William County Office of Planning, so he made a visit to check out the place.

What he saw was unimpressive: a creaking old "office building" in Manassas so crowded that some planners huddled at desks in a damp basement, where pools of water could be seen through cracks in the floorboards, and 20 employes ran footraces to use the only bathroom.

Horrified, Snyder took the job anyway, rising to become director of the office. Eight years later, like so much else in the county, almost everything has changed in the planning office, which has doubled its staff and moved to more comfortable surroundings in the county's new government headquarters in eastern Prince William.

One thing has stayed the same, though: The planning office remains the chief local agency trying to accommodate and control development in a county that continues to be buffeted by the dizzying pace of Northern Virginia's growth.

"There isn't a piece of {undeveloped} land in this county that doesn't have someone looking at it," said Snyder, who recently resigned to become the head of Northern Virginia's leading development lobby. "When there's millions to be lost and made, there's no holds barred."

County Executive Robert S. Noe Jr. appointed John Schofield, a five-year veteran of the county government and most recently the deputy director of planning, to succeed Snyder, who is becoming chief executive officer of the Northern Virginia Building Industry Association. Schofield's annual salary will be $52,200.

In an interview, Snyder gave parting assessments of Prince William's record in managing growth, and the challenges and limitations facing the planning office as it goes about that task.

The challenges include an astonishing volume of work. In the last five years, the number of land use cases handled by the planning office has more than doubled, to almost 200 development applications annually.

A persistent limitation is retaining employes in an office that has been marked by high turnover as planners leave to take higher-paying jobs with other localities or in the private sector.

In recent months, resignations have left some positions in the planning office unfilled, prompting some in the development industry to complain that it is taking too long to get questions answered and applications reviewed. At one point last summer, the office had eight of its 40 staff positions unfilled, and the revolving-door syndrome, a common problem in planning agencies around the region, has shown little sign of abating, officials said.

"It's a mobile profession," said Snyder, adding that he nonetheless laments the speed with which some young planners skip to different jobs. After two decades as a public employe in Prince William and elsewhere, Snyder said he feels no regrets about himself moving to the private sector.

To an outsider, the duties of the planning office can seem mind-numbing: analyzing applications for "rezonings" and "special exceptions," using highly technical criteria that go by such names as "floor-area ratios" and "traffic generation."

Camouflaged by this jargon, however, are many of the most potent issues in suburban politics: What will happen to the county's remaining open spaces? Will developers or taxpayers foot the bill for new school sites? How much traffic will a new subdivision add to Prince William's congested roads?

More than any agency, the planning office is the source from which elected officials on the Prince William Board of County Supervisors compile and assess the information they need to resolve these and other controversial issues.

When a developer submits a land-use proposal for a new subdivision or a shopping plaza, for example, the county's planners conduct studies or oversee private studies researching the impact on area roads, sewers and other public facilities, as well as whether the project conforms with the county's "comprehensive plan" -- a document designed to channel Prince William's long-term growth.

Without such a long-term perspective, Snyder said, the supervisors' land-use decisions "would be like trying to put together a puzzle without a picture on the front of the box."

Essential to solving this puzzle is what in the parlance of planners is known as the "proffer system." Proffers are concessions -- such as road improvements, parkland or other public improvements -- that the county extracts from developers in exchange for approval of their projects.

Virginia has among the most conservative property rights traditions in the nation. Local governments do not have the legal authority to reject new office or residential projects simply because they would prefer that the projects not be built -- a fact lost on most residents, local politicians contend.

By negotiating aggressively for proffers, however, Prince William has done a good job blunting the costs and other adverse effects of growth, Snyder said, despite what he acknowledged is a widespread feeling among many residents that growth is "out of control."

While planners tirelessly insist that intelligent growth policies cannot be reduced to a simple issue of pro or con, Snyder and Schofield acknowleged that on many major development decisions two easily identifiable factions quickly emerge: civic activists and nearby residents who want a proposed development rejected or substantially altered, and developers who want their project approved quickly and without modification.

Schofield, the new director, said residents who oppose a development or certain aspects of it are well-advised to do their homework on land-use policies but also to set their sights realistically.

If a proposed project conforms with the comprehensive plan, unyielding protests from civic activists, no matter how heartfelt, are likely to fall on deaf ears from the county board, Schofield said. On the other hand, if residents are willing to negotiate on specific points -- a larger buffer of trees, for example, between a proposed new office complex and their homes -- they often meet with considerable success.

"The people who are most effective are the people who are realistic, who know the rules," Schofield said.