I like the old method of using Chlordane which you can't do anymore. Next is going with a similar chemical treatment around the foundation which is now good for 5 years.
I don't like these baits cause they need to get to the bait to start with (no guarantee of that). Use both chemical and bait. Check around with other companies and see what they will do. Most are going to this type of system. They get paid for coming back and checking the baits on a somewhat regular basis. Talk to your neighbors and realtors to see what they and others are doing. Instead of killing termites, you usually just chase them down the block. Chances are someone chased them down your way to start with.
I haven't used Terminex but have used the store bought brand which Terminex and others would say is inferior. They get wet and turn to mush and the dog digs them up and chews on them.
You can buy the chemical locally in many states and over the internet and do it yourself. Still will cost $300 to $600 for the chemical plus digging a 6" trench about 6" deep all the way around the house. The chemical is expensive and some companies got a bad name for scrimping on the chemical they were putting in.