I don't know about anywere else but around here you have to have an up to date survay before you can transfer ownership of a house.If a vendor has a survay (regardless of how old) he is required to turn it over. If he doesn't or its out of date, the purchaser is required to have a new survay done(at his cost).
Any new buildings or additions on the property would be recorded on that survay and thats what the taxes are based on. If its on the survay, your already paying taxes on it regardless of when it was done.
A short story.
Ocasionaly the survay companies will recheck their survays at random to ensure accuracy. My house was one of them. By the time they did the second survay, some changes had been made. Mostly it was fences. Some were removed and some were replaced and relocated to properly reflect the property line. There was also a small deck that was replaced and a new out building.
The guy who did the first survay had to come back and check with us to ensure that the changes were actualy made by us and that he didn't screw up the first survay. Apparently his job was on the line.