Grumps might have to rethink criticising the “kids of today” and millennials in the same breath, as the oldest among them are not so young any more. At 22, the youngest millennials are still fresh-faced and leaning on their better-off Gen X or baby boomer parents. And the oldest millennials are 38 – not really kids by any metric, but conceivably still in their parents’ pockets.

Maligned as feckless, entitled, absorbed by screens and uninterested in sex, millennials have been a favourite punchbag for some time. Generation Z , born from mid-1990 on, are next in line for a kicking. After them are Generation Alpha, the first group of millennials’ children, born from about 2011 until 2025. Henry Rose Lee, the intergenerational speaker and author, describes them as “millennials on steroids”. “The oldest millennials didn’t really grow up with digital technology, though of course they’ve inherited it and made it their own,” she says. “People under the age of 22 have virtually grown up with it in its increasing sophistication. They are thus quite different from us oldies.”

Attempts to stratify society have endured ever since the social researcher Henry Mayhew strolled round Victorian London’s slums. But is defining generations useful? “You have to be careful about it,” says Karen Rowlingson, professor of social policy at the University of Birmingham. “But we shouldn’t ignore generational divides. Younger people are, on average, facing many more challenges. And, certainly, inequalities within that generation [millennials] are greater.”

Lee says labels can be helpful in understanding how technology, economics and politics have affected different age groups. Millennials, for instance, are the first generation since the 19th century to be worse off than their parents – a misfortune that Gen Z and Gen Alpha are likely to inherit. But, for Lee, a greater concern is the risk of devaluing individuality. “What I normally say to people when I’m presenting a workshop is: ‘We’re going to label the hell out of things, but please don’t do it outside this room.’ Because as soon as you label somebody, you’re judging them.”