A good understanding of the property and of its history is important in anticipating the need for ultrasonic investigation.  Planning 2-3 months in advance is always advised in order to coordinate schedules and make all preparations – an issue that becomes more important for larger projects.  Airfares escalate dramatically for hurried plans; typically requiring 3-4 weeks advance booking to acquire reasonable airfare.  The $295 flight to Chicago available a month prior escalates into a $2,100 ticket a day or two in advance.  Since it is necessary to open walls to provide access, projects related to dual temperature piping, domestic water, and sanitary waste service often require as much as 6 months or more for the building management to negotiate with tenants or apartment owners the specifics of disturbing their space.