How old does a volcano have to be to become extinct?

Villarrica is among the most active volcanoes in South America

That’s a surprisingly tricky question; let me start with what is hopefully a helpful analogy. Volcanoes aren’t like old people who might retire from their job or kick the bucket at a predictable age. Volcanoes are much more like a rock band. Most are one-hit wonders, many produce some great hits for a while and then slowly disappear, and others keep rockin’ on for ages.