Final answer:
When someone reviews all documents at the courthouse related to a property they want to buy, it's called due diligence. This ensures they are aware of all the details, including any potential issues and tax obligations.
Step-by-step explanation:
Once a person has gone to the courthouse and reviewed all documents pertaining to the property he intends to buy, he is said to have exercised due diligence. Due diligence in this context involves a comprehensive review of all available information about a property, which may include reviewing public records, property titles, past deeds, easements, zoning laws, and any other documents related to the property's history and use. This process ensures that the potential buyer is fully informed about the property and any obligations or issues that come with it, such as taxes owed based on its assessed value. In historical contexts, such due diligence might have been based on declarations of property by inhabitants for tax purposes, where owners declared their estate under oath to establish its value for taxation.