Although such events don’t happen very often in these lean real estate times, the agent, Michele Kolsky-Assatly of Fort Lee, had achieved something that doesn’t happen much anywhere: an accumulated $1 billion in home sales. Company officials said it was the equivalent of selling a house a week for each of the 18 years she had been their agent.

“How’d I do it?” Ms. Kolsky-Assatly said last month in a phone conversation. “Well, for the first 15 years, I never took a day off.” She isn’t proud of that, she added, as the work came at the expense of time with her spouse and children.

An even more compelling question might be: How did she and other top-selling agents maintain the pace over the last three years — as prices fell roughly 20 percent statewide, inventories grew fat, and total sales volume went slack?

Last year, Ms. Kolsky-Assatly had $71 million in sales, all of them in Bergen County. In a list of the country’s 250 top agents compiled by the real estate consulting firm Real Trends, she was ranked 51st in sales volume.

Another Coldwell Banker agent, Elaine Pruzon of the Short Hills office, came in ahead of her, recording $94 million in closed sales in 2010 and ranking 32nd. Arlene Gonnella of Weichert Realtors in Short Hills came in just behind Ms. Kolsky-Assatly, selling $68 million worth of homes and ranking 61st.

These agents are working in tony territory, where the houses and penthouses have high price tags. ButMs. Kolsky-Assatly asserts that she consistently markets houses across a range of price points. “I’d sell a doghouse, if I could fit through the door,” she said jokingly. She was recently hired to sell one of the most expensive houses in New Jersey: the $28 million Henry Clay Frick mansion in Alpine, which has been on the market for more than three years. The home, set on 14 acres (accommodating 14 horses), is ensconced in Forbes magazine’s “Most Expensive ZIP Code” for 2011.

At the lower end, she has a two-bedroom Teaneck condominium, listed for $479,000.

“Whatever the price point,” she said, “I would say my strength is, well, do you know what a gift of gab means? I’m not bashful. I tell the truth. I say to people right off: I’ve done the research, here it is, and this is the best you are going to get. If they ask me when the market is going to turn around, I say, how the heck do I know?”

Also, she cited an old-school commitment to print advertising. “I am willing to spend money to make money. My clients are still looking at those newspaper ads in the mornings over a cup of coffee. I know it, and those ads tend to grab them in a way that online advertising doesn’t necessarily.”

Other documented top-sellers say they see their success as essentially flowing from true grit in a marketplace fraught with stress and frustration.

“Every agent in every town in New Jersey will tell you they have to work twice or three times as hard as they used to in order to complete any transaction,” said Gordon Crawford, who leads a six-person team at Re/Max Properties Unlimited in Morristown that sold $81.6 million in 2010 and was ranked 60th among teams.

This year, his team will close about 120 sales, versus 108 in 2010, for a significantly reduced dollar volume of about $56 million, Mr. Crawford said.

He described an instance of working with sellers in Sparta who insisted on listing their house for $639,000, although Mr. Crawford pointed out that with about 275 houses on the market in Sparta, $550,000 was the appropriate figure. “Seven months later,” he said, “it is listed for $500,000, so offers could start coming in around $490,000.”

In Margate, a barrier island community near Atlantic City, the top sales producer, Paula Hartman, runs a team at Prudential Fox Roach Realtors that did $52 million in business last year, and she expects to do about the same this year. “But we sold 100 houses last year, and this year it will be about 150,” she said, “each one requiring maximum energy.”

With today’s tightened mortgage-lending standards and wary property assessors, Ms. Hartman said, brokers have to “sell every house twice — once to the buyer, and once to the bank.”

“In this climate, you really have to love your job,” said Ms. Hartman, whose handle on Zillow is RedHeadedRealtor. “I started out as a dental hygienist, and every day I think about how grateful I am not to be cleaning teeth.”

Ms. Hartman, like Ms. Kolsky-Assatly, has bolstered her daily work life with family: Both women now have sons who work alongside them; also, Ms. Hartman’s husband is her computer systems handler, and her daughter does office support work.

“I think that is a huge part of success,” said Ken Baris, the president of Jordan Baris Realtors in West Orange, founded 60 years ago by his father, who still works with him. “The knowledge you gain by osmosis, and the level of trust between the partners is incomparable.”

His agency does not publicly report its sales volume. But Mr. Baris says he employs computer analytics — his own and others’ — to rank agents on their “sales and negotiating ability.”

“Sometimes,” he said, “an agent will be a really prolific lister, and have their name on all the signs, and everybody thinks they are really popular, but then have a shockingly low percentage of listings taken to sold.”

Also, Mr. Baris said, he analyzes what percentage of an agent’s listed properties are relisted with the agent when the contract expires without a sale. And he assesses agents by the proximity of sales price to list price in each transaction — whether they are representing a buyer or a seller. “It’s not always perfectly clear what they are doing right,” he said. “Whatever it is, we want to go with it.”