We had a termite check this year. We had pest control check our house and treat it for every kind of creepy crawly. None found. We did find two big possums though, which were caught and released nearby.
Yes, annually. One thing about white ants - don't know they are there until it's too late. If you find out they are in your house then you are too late & they may have done thousands of dollars damage ;((
Better to be safe than very sorry!