Some types of maggots found on corpses can be of great use to forensic scientists. By their stage of development, these maggots can be used to give an indication of the time elapsed since death, as well as the place the organism died. The size of the house fly maggot is 10–20 mm (⅜–¾ in). At the height of the summer season, a generation of flies (egg to adult) may be produced in 12–14 days.

Maggots are bred commercially, as a popular bait in angling, and a food for carnivorous pets such as reptiles or birds. Due to the increasing popularity of maggots, a maggot vending machine has been installed in the English county town of Northampton.^{[citation needed]}

Various maggots cause damage in agricultural crop production, including root maggots in rapeseed and midge maggots in wheat. Some maggots are leaf miners.