Most common flies live for only a few weeks, with adult houseflies typically surviving about 15–30 days, depending on temperature, food, and species.

Houseflies: the usual culprits

  • The average housefly (Musca domestica) lives roughly 15–30 days as an adult in normal conditions.
  • From egg to adult (egg → maggot/larva → pupa → adult) the whole life cycle can be completed in about 2–4 weeks in warm, food-rich environments.
  • Indoors with steady warmth and food, some adults can make it close to a month, occasionally a bit longer.

That annoying fly around your kitchen is usually on a 2–4 week timer, not months or years.

Other flies and their lifespans

  • Fruit flies (the tiny ones around bananas) develop from egg to adult in about a week and adults can live around 30–50 days under good conditions.
  • Tsetse flies (in Africa) are an exception: females may live 1–4 months, while males usually live only a few weeks.
  • Many small “gnat-like” flies also have total lifespans on the order of a few weeks, strongly influenced by warmth, moisture, and food availability.

What affects how long flies live

  • Temperature: Warm (but not extreme) conditions speed up growth and can extend adult life compared with harsher outdoor environments.
  • Food and water: Without access to moisture and nutrients, houseflies may die in just 2–3 days.
  • Shelter: Being indoors protects them from predators and weather, so they can reach the upper end of their normal lifespan.

Quick life-cycle snapshot

  • Egg: laid on decaying organic matter or food waste; hatches in about 12–24 hours for houseflies.
  • Larva (maggot): feeds for roughly 4–7 days before pupating.
  • Pupa: transforms into an adult in another 4–6 days in warm conditions.
  • Adult: lives around 2–4 weeks for houseflies, longer for some species like fruit flies or tsetse flies.

TL;DR: For “how long do flies live for,” the simple answer is: most household flies live about 2–4 weeks, though some species can stretch to a couple of months in ideal conditions.

Information gathered from public forums or data available on the internet and portrayed here.