When Mary Gannett was ready to retire from Book Court, the beloved Cobble Hill bookstore that she and her husband ran for more than 30 years while raising their family in the apartment above, she crossed Atlantic Avenue to Brooklyn Heights.

“It was a big transition in my life,” she said, “and it was a big change.”

Her marriage was ending. There was a lot of upheaval and construction in Cobble Hill. She loved everything old, but a real estate agent persuaded her to look at one of the few new buildings in the neighborhood, 172 Montague Street.

Now she rents a two-bedroom apartment there with panoramas of Lower Manhattan from her terrace and a 360-degree view from the roof deck. She and her partner, who is also retired, especially enjoy walking the Promenade, the walkway overlooking the East River that was created when Robert Moses ran the Brooklyn-Queens Expressway around the neighborhood instead of through it.

“That’s my spot,” said Ms. Gannett, 64.

Ask a longtime Brooklyn Heights resident what has changed and the answer is likely to be a cautious “not much.” Preservation efforts have been fierce for decades; Brooklyn Heights was the first New York City neighborhood to be named a Historic District, in 1965. The Brooklyn Daily Eagle, which was founded in 1841 and counts Walt Whitman among its former editors, continues to train a keen eye on the neighborhood, as do several hyperlocal blogs.