Duodecades are superior to decades, and we can take overlapping pairs of duodecades as "generations" to solve the dividing line problem.
Duodecades:
* 1968-1980
* 1980-1992
* 1992-2004
* 2004-2016
* 2016-2028
* GenX: 1968-1992
* Millennial: 1980-2004
* GenZ: 1992-2016