Here is come critical thought about grouping by age, especially challenging the danger of reading too much into fashionable views of groups such as millenials.
In my view assuming any individual will conform to the norms of a group is risky since an individual is just that, individual and complex. However it is interesting to see how millenials are different to baby-boomers en masse, and how history and evolution change us.
For other such interesting comparisons this article suggests we should define workers by a ‘psychographic’ group with similar wants and needs. Working and social styles groupings might well be interesting; just so long as we don't try to pigeonhole people! It might also be interesting to see the banding that occurs (.e.g as millenials currently 18-34) and how we like being banded within them.
I use this link to the CIPD article that also suggests that development can happen at any age, if we're open to it. Do you agree?
http://www2.cipd.co.uk/pm/peoplemanagement/b/weblog/archive/2016/12/12/rethinking-age-at-work.aspx?utm_medium=email&utm_source=cipd&utm_campaign=cipdupdate&utm_term=408929&utm_content=141216-8180-26526-20161214072941-Read%20People%20Management%20%27s%20feature