There are many species of flies, but only a few are common household pests: house flies, stables flies, and blow flies.
All flies undergo complete metamorphosis. Adult flies lay their eggs in waste or decaying organic material. These eggs hatch into larvae – sometimes called maggots – and complete their development there. They emerge as adults in as little as a week.
The best way to resolve fly problems in and around your home is to remove the materials flies lay their eggs in. These can include garbage, rotting fruits, pet and livestock wastes, and animal carcasses.
Using door and window screens, or keeping doors and windows closed, will help keep flies from coming indoors. You may also want to use sticky fly traps to eliminate small numbers of flies indoors. Pesticides are not usually necessary for household fly problems.