How long is a single "generation?"

Native speaker’s answer
Rebecca
Well, "generation" is often a very relative term. If we talk about demographics, we have clear delineations for age generations (baby boomers, millennials, Gen Z, and so on). But in other contexts, it's hard to determine. Generally, you can think of a generation as encompassing around three decades. However, it might not necessarily indicate a specific period of time, but rather a stage in the development or history of something, like politics. Ex: I think Serena Williams is the athlete of our generation. Ex: Who do you consider to be the defining individual of this generation?