Some New Yorkers have a use-what-you-have mentality that allows them to see an ordinary old coat closet as a gift of more square footage in a city where every inch of interior real estate counts. With a little work and a lot of vision, they’ve discovered that the smallest and most unassuming space can become a bedroom, a work space, even a secret cocktail bar.

When Jane Herro, 30, a jewelry designer and a saleswoman at Realty Collective, first saw her one-bedroom apartment in Red Hook, Brooklyn, she was most excited by the small coat closet behind a curtain next to the front door. It looked just big enough for her jeweler’s bench.

“I worked in my bedroom in my last place,” said Ms. Herro, who is originally from Milwaukee, and came to Red Hook after stints in Prospect Heights, Brooklyn, and Hell’s Kitchen in Manhattan. “When I saw this place I thought, that’s perfect. I love working from home, but I didn’t want to look at my work all the time, so I needed a closet where I could close it.”