Are you selling your condo? If you are, consider using as your agent someone who lives in the building.

That's what this real estate agent advises:

I’m often asked by clients whether or not they should consider hiring an agent that is also resident of their building to represent them during the sale of their apartment. There is no cut and dry answer, obviously as it depends greatly on the individual agent. That said, many buildings have very solid agents living among the residents who often bring much more to the table than an outside agent possibly could.

Complete story: Hiring a Resident Broker to Sell Your Apartment - By Douglas Heddings, True Gotham