The area where I live is infested with termites.
Even though we sprayed the land before we built, they continually reappear.
Over the 20 or so years that we have lived here, we have tried many different local companies.
After year two/three, they disappeared with our annual fee.
The current one that we use (Ecopest) have been brilliant.
We have been using them for about 12 years. Not the cheapest but by far the most professional.
They come every month and spray (a must for termites) and even come on request if there is a new problem.