Termites need food and water and access into house. If foundation is intact and no interior water turn to outside. Make sure any mulch is not up against the house, but rather at least 6 or more inches away from foundation. Buy mulch that has been heated to high temperature to reduce introduction.

Grade soil away from the home so water does not pool near the foundation and have adequate sized gutters and downspouts, the latter should end at least ten feet from foundation. Look yourself outdoors near the foundation (they are small and light colored) and/or get a termite inspection yearly.

I wouldn't treat preventatively without confirmation, but that is just me. Boric acid (Borate) is one option.

I've seen termite damage in my first (not structural), and a swarm by my second.
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We had someone come by and inject stuff a few feet into the dirt all around for each one. No problems since.

Yes they do need termite treatments but generally it's not spraying, it's those bait stations they put in the ground. I've seen lots of termite damage to beams in basements & even a case of termites swarming out of the baseboard in a brick 1920s house in nw.

Home from the 1930s... no wood in contact with soil...
DH wants to spray but I'm hesitant
No obvious signs of termites.
Your thoughts and experiences?