The stairs creaked in Jen Gorgano’s childhood home. Recalling those sounds makes Ms. Gorgano smile. “Growing up, we would always know who was running up and down the steps by how loud it was,” she said.

The creak is still there. So is Ms. Gorgano. She is in the process of buying the four-bedroom house in Commack, N.Y., from her mother, who now divides her time between Florida and her partner’s Long Island condo.