In East Harlem, Miriam Cruz , a retired nurse’s aide, is almost always home so a couple of neighbors asked her to keep their packages for safekeeping. Soon, word spread around the building, and over the past five years she has opened her door to thousands of packages.

Nothing has been stolen on her watch — unlike the box of Nike sneakers that disappeared recently from outside another apartment. “Put Nikes in front of anyone’s door, of course they’re going to take it,” she said.

Ms. Cruz, 69, said her family did not want her to do it at first because of worries about strangers showing up at her door. She did it anyway. Now, during the holidays, she has boxes filling her hallway and spilling into her bedroom. If neighbors do not pick them up, she posts reminder notes on their doors.

Ms. Cruz, who is known as “Ma” to her neighbors, refuses to take money so they have thanked her with cake and chocolates.

“This is something I do,’’ she said, “because I love my neighbors and I want to pay it forward.’’