I've noticed that around twice a year, regardless of season, the house will be invaded by a total barrage of flies. And they won't just disappear either, you have to go out of your way and terminate them.
It seems to me, to be a seasonal thing, but then I think, I could avoid biannual fly infestation by keeping the house a little cleaner.
Anyone else noticed this phenomenon? Explanations and combat strategies, please.