Believe it or not, we still have a few flies hanging around after all this time. I eliminated all of the fruit that I had been putting out in fruit bowls, put wine out, got professional traps, and found out they had been breeding in the sink drains both in the kitchen and bathrooms so got professional foaming spray for the drains.
I found out they have a 10 day gestaion from egg to adult. Every time I thought something was working (like the wine), there would be another group a few days later. I hope I never get those things again!