Or they might be sacrificing an item’s potential, as Sharon Begley writes in her book “Can’t Just Stop: An Investigation of Compulsions.” Any piece of clothing could potentially be recycled in a craft project. Empty cardboard boxes could be used to store things in the future. A newspaper article must be saved because it has vital information that a friend might need.

Frank Durant, who works for Charles H. Greenthal Management and is the general manager of the Seward Park co-op complex on the Lower East Side, said he deals with about five to eight such cases a year.

“I’ve seen places where you can’t walk in the front door,” he said. “Walls filled with pizza boxes and Chinese takeout containers.”

When confronted with a situation like this, what is the best way to proceed?

The building management and board should be notified if a tenant with a hoarding problem is discovered because the clutter is the source of a leak in another apartment, causes a foul odor or is the epicenter of a rodent or insect infestation, said David L. Berkey, a partner at Gallet Dreyer & Berkey LLP. In this case, the tenant is breaking an agreement (whether it is the proprietary lease, house rule or rental agreement) to keep the apartment in good living condition and is legally required to clean the home to the point where the nuisance ceases to exist.

Before taking any formal legal action, Mr. Berkey said, boards and landlords should first confirm that the tenant is aware there is a problem and should look for family members who can help. The goal of the board or landlord is to maintain a safe space for all the building’s residents, including the hoarder, so finding a social services agency, a civic or religious organization, or a nonprofit to assist should also be a priority. And if the tenant is elderly, a geriatric care manager could be called on as well.