I didn't really believe and I didn't do what I was supposed to. I'm confessing because it's information you all should have.
I started last spring with new hives etc. and had 8 strong colonies by fall. I started right in and fogged every 2 weeks and used the cord. I never saw a mite. I half believed that I wouldn't have seen any if I hadn't fogged. It was too easy and I got cocky. I had to travel from Aug 15 to about Oct 15 and there was no fogging in that interval. I did get 1 or 2 foggings in when I returned in Oct.
All my hives died and I assumed it was the cold. Maybe that helped but when I finally checked the SBB boards they were replete with mites. I'm a little ashamed.
This unhappy information proves 2 things.
1. FGMO works and kept the mites below observable thresholds.
2. The protocol works and one can't get lazy.

I stopped fogging when they went into cluster. I thought this was part of the system, especially here in Ct. Today Juan was talking about fogging in winter. I wish I had done that but wouldn't that have broken the cluster? I'm starting over with new bees and will use FGMO again. Juan, I like your idea of fogging at night. It seems to make eminent good sense! It's the first time I read that.