First, I read about the gas explosion in New York City caused by a 150 year old ruptured gas line. Now it's a 9 alarm fire in a bunch of Boston Brownstones built in the late 1800s. That fire killed fireman and civilians. When is a building too old to live in safely. Rooms in a building can be remodeled, but it is usually the same sewer system, gas lines, power lines, dried out structural timbers and rotting brickwork. Is it safe to think buildings past a certain age are still habitable? I wouldn't live in any building that was older then I am. :-?