Here in Kansas, termites are the norm. When we lived in town, if one house in the neighborhood had their place treated for termites, the following year the neighbors had to, then down the street it went. When the cycle started in the neighborhood of our friends, they had the outside of their place treated right away and signed a contract for monthly checks of bait traps. I don't know how much they pay each month, but this has been going on for several years now. I bet he's spent $1000 for those monthly checks by now. Ouch.
Edited to add: I talked to my friend yesterday. She said they spent $800 to $1000 just to have the Tox-eol bait traps put around their house. The cost is determined by the number of traps they say you need based on how large your structure is. Now they pay $250 a year to have the traps checked monthly. Double ouch.
The termites serve a purpose in nature, being part of the decomposition cycle. That doesn't mean that I like them. And even though I try to do the green thing, I'm not willing to risk my home and hard work by spraying with soapy water and keeping my fingers crossed. Termites were in a couple areas on our property when we bought it, so we considered it a 'known termite area' and acted accordingly.
After we got our foundation done, I bought several boxes of borax (20 Mule Team, Borateem) and threw it all over the crawl space area plus inside and outside of the foundation (before and after backfilling). One neat thing about borax is that it keeps working for 2-3 years after it gets wet vs. DE that is ineffective after it gets wet. A couple years later we were in the crawl space and saw one spider, that's it. I was impressed.
Fast forward two years and we're adding on to the side of the house and attaching to the old garage. Bill thought he saw active termite activity on the back of the garage. *Sigh* So we called the local pest control guy and paid him $700 to treat the outside of the house and garage. Come to find out, it wasn't termites that Bill saw. I wished I would have done the borax thing around all the outbuildings and then just kept an eye on them, you know? But at the time, we thought we'd be tearing it down in the future.
I learned from the termite guy that ants hate termites. In the areas where we know there was active termite activity, there was also major ant activity. He also told me that the purchased termite baits were 'iffy'. Sometimes they worked, other times they didn't. Well, he also makes a living spraying and doesn't live in the cheap seats in town, either. But if they are 'iffy', I might as well make my own and check them myself.
So, instead of doing commercial bait traps, here's how to make your own. Simple stuff. First, dig a hole at least a foot deep, about 6' away from your building. Throw in a chunk of wood, like a hunk of scrap 2x4. Put a short piece of 1" PVC or any kind of metal pipe in the hole. You want it to be long enough to reach the wood yet short enough so it's not really sticking out of the ground too far. Pour sugar water on the wood, let it soak for a bit, then fill the hole back up with the dirt. The only reason for the pipe is so you have some way to add some more sugar water every once in a while. PVC will degrade over time in the sun, but use what you have around there. If your bait trap is in an area where you mow, obviously you want it short enough to mow over it, or have it stick way out and mow around it.
If there are termites around there, they will be attracted to the wet wood. The sugar will attract the ants initially and they'll take care of the termites. Next year, dig up one and see what ya got. No termites and ants? Good deal. Put the trap back together. Repeat on the next trap. The traps aren't going to create termites, but hopefully if there are any in the soil, they'll aim for the trap instead of your house.
Is this a sure fire thing? No. Will termites that are already in your building leave for the homemade trap? No. But it's cheap, green and it might save you a few bucks.