We used Terminix to eradicate a live termite infestation but then they ended up talking us into rodent control and wasp and bee control, neither of which we really needed to do. The termite thing was necessary to keep our house from falling down but that is a one-time-only treatment with an annual checkup. They make their real money off the month visits to check for mice and wasps and stuff. They put a lot of poisons down. I had my doubts as to how necessary it was and how effective it was, but it wasn't until they sprayed insecticide out of our kids' bedroom window onto a wasp nest and I saw the mist drift back into the room onto their play table that I decided we did NOT need it. Wasps are not worth that and we could always use traps for mice if they ever came back (which they didn't).
Termites: ok. The rest: not so much.