It has been nearly two decades since New Yorkers faced their last doorman strike, but as the deadline for a new contract for building workers approached, the questions being posed throughout the city remained largely unchanged on Sunday.

Who will safeguard my apartment as I sleep? Greet my children when they come home from school? Accept deliveries? Clean the hallways? Sort the mail? Operate the elevator? And who, for goodness sake, will let the cleaning lady in?

Residents, co-op boards and building management companies have been busy planning for the sudden complications that could come at 12:01 a.m. Wednesday with the possible departure of the building workers who, among many other things, hold open the city’s doors.

The Realty Advisory Board on Labor Relations has distributed a preparedness manual with recommendations for keeping buildings in operation in case of a strike. “A strike is not pleasant, nor should it be taken lightly,” according to the 45-page document. “During a period of work stoppage, pressures and problems develop which make building management very difficult.”