Effective Age is the counterpart to a property’s Actual Age. While the former refers to the date a property was built, the latter is more of a sensorial depiction of its age; the age the property appears to have.
So, in a way, you can impact on your house’s Fair Market Value by making your house’s effective age younger than the actual age really is. If you maintain the house in good standards and do some renovations, the house might appear younger than it actually is.
But beware: this whole discussion of effective age versus actual age appears more frequently when trying to bring the fair market value down. So, if you’re the property’s seller, never forget to keep an eye on its conditions. Never let go of the proper maintenance and invest in renovations whenever you can.