Termite maintenance

Does anyone use anyone for a regular termite maintenance? I was wondering how often they come (1/month, etc.) and any est. costs?

Our prev. owners had some small issues, which they took care of right away, and everything is fine.
However, I just panic at the thought of all those munching bugs coming back :)

We keep meaning it pick our neighbor's brains about it, but in the meanwhile, any info you all have would be great.

I know I can probably just call someone from our pennysaver, but i was hoping to get some feedback on people that use the services themselves and see how they like them - if they are worthwhile, etc.

Thank you!

Our home has the Sentricon system which is supposedly the best for Termite prevention. We haven't found a exterminator yet though so I don't know how it works. I'll post when I find out.