Termite activity is so easy to spot I do my own inspections. The damage they can cause is minimal financially (if not overlooked for years) compared to paying the exterminator for a yearly contract to inspect. I have always seen the swarmers inside the house which is a dead giveaway that they are there. If you find damage, run to lowes and buy repair material, rip out the old, treat with poison and put up the new.
