My house has had a lot of flies. I mean, A LOT of flies. I think a bag of potatoes I bought at the market must have been a larvae bed for them. During my vacation time I've been spending ten to twenty minutes a day walking around with a spray bottle of 409 and a roll of towels and disposing of them. I would prefer to have an electric fly swatter, but they don't seem to carry those at Albertson's.

I don't know the exact data, but I have been roughly keeping track of the fly population in the house since I've become my vacation, and I've noticed the following statistics:
Day 1: 50+ flies disposed of
Day 2: 20+ flies disposed of
Day 3: 5 flies disposed of

This trend would tend to indicate that the flies are losing the battle, or they've begun to burrow into the walls where I cannot see them. I have also noticed that the flies I am disposing of are younger and more sprightly. Hmmm... I guess I'll have to wait out another pupal cycle to see whether or not I've truly won the battle.