Does anyone know the chance of reoccurance of termites after treatment with Termidor by a professional?

the chance for recurrence is unfortunately very good. Yes, reinspect. With the possibility potentially being pretty severe and assuming that your covered for the next 7 years, that's an awfully long time for the termites to do what they do. I would advise that you contact the same company with your fears and ask that they do a follow up to insure that the treatment they did for you is still working.

We had it done in the condo and I too thought I saw a small swamer awhile back and sprayed them and I haven't seen them since. Actually I never did see one at a time but 2 years in a row I had a large swarm of them near my dinning room sliding door. It seemed like millions. I killed them with raid and they died quickly but I was scarred the first time cause I was afraid they were going to start flying around. I don't know if you ever really get rid of them completely. Let's see what others answer.