I'm in a summer-long project of remeasuring the 10 courses for the Westport (CT) Summer Series, the 2nd oldest races in the state. Five of the courses have remained completely unchanged since their original certification back in the late 90s; four have had the start and finish moved/adjusted in the intervening time (we used a calibrated bike to make sure both points were moved an equal distance).
One thing I have noticed during the rides is that while the roads' configuration have not changed many houses on the routes have - lots of tear-down/rebuilds in this part of the world (much of Westport is known as the "Gold Coast" b/c of the wealth that resides there) with the result that driveways get rebuilt in different places, making "7 feet past driveway #122 Hillspoint Rd." no longer valid as a split description.
Fortunately, I've found the overall distances haven't changed, so aside from updating the split location descriptions the original maps can be used for the new certification paperwork.