“I like to plant flower boxes, and I change them weekly and water them if the owner forgets to,” she said. “I often go to the flower district early in the mornings or out to the big nurseries on Long Island to get just the right thing to put in a pot on a brownstone stoop. But, then, I’m a bit of a perfectionist.”

Ms. Goldman also routinely buys new trash cans and paints the street address on them in an effort to make the best impression when prospective buyers arrive to see a listing. “Some people carry plastic bags for dogs,” she said. “I carry them so I can pass by my listings and pick up trash.”

Image Nichole Thompson-Adams, of the Corcoran Group, has been known to pay for cleaning, painting and decluttering. Credit... Michael Falco for The New York Times

Other brokers emphasize luxury services.

Karen Heyman, a broker in the SoHo office of Sotheby’s International Realty, always hires car services to ferry potential buyers to see her Brooklyn listings. She says it’s worth it to her, in the end, to cover this expense herself.

“The bottom line is that we’re all independent contractors,” she said. “Our offices have certain budget formulas, but I find those restrictive. If I think there’s something I can do to increase the likelihood of a sale, I’ll do it, no matter what.”

Agents also use their commissions as leverage in making deals happen.

“Say a seller’s at $900,000, and a buyer won’t go higher than $895,000,” said Michael Signet, director of sales at Bond New York, which has five offices in Manhattan. “Our broker might call the other broker and say, ‘You pick up $2,500, and we’ll pick up $2,500.’ That way we don’t lose the deal.”

Because the New York City market is growing increasingly stressful  sellers worry the peak has been reached and potential buyers are reluctant to commit for fear of paying too much  more is being asked of brokers.