“There’s an aspect of masculinity and machismo,” said Mr. Capulong, who carries a pocketknife himself. “You can do everything on your own and you’re not helpless.”

Nigel Barker, 43, a New York-based fashion photographer, has noticed that the pocketknife has become de rigueur among the young hipster assistants he works with. “Almost part of their uniform is to have that knife on that belt or in that pocket,” he said.

Mr. Barker has several pocketknives of his own, including a Swiss army knife, but he isn’t new to owning one. He got his first blade as a boy in the countryside of England and has carried one ever since, excluding the years he worked as a model, when there was, as he put it, “no use for me to have a knife.”