Usually, the company doing the pre-treat should send out a renewal before your 5th anniversary. I think that's wrong.
Exterminators can treat just as well when the house GETS termites.
In fact, even though they treated it, it can still get termites. Who knows, maybe you'll be transferred to San Diego or something, then the money you spent for the termite job will be for naught. Very important - cheaper when it's done this way, and much more effective. Naturally, this is not all written in stone. What normally happens is that, for some reason, the stoops don't get treated even though the rest of the house has been treated.