If you live in a certain area with high temperatures and humidity, your house might be prone to attract a lot of fruit flies. They are harmless but sometimes you will need to control them using DIY methods such as this involving a water bottle, apple cider, and more simple household materials.
It seems our house has been overrun with fruit flies this fall with all the garden vegetables fruit in the house. So we built a DIY fruit fly trap to try and reduce the “herd”. My wife read about making a fruit fly trap from a water bottle so we gave it a try.