linguistic:voice_change, quality:corruption
Time co-ordinates

For a variety of reasons, timelines on young adulthood cannot be exactly defined—producing different results according to the different mix of overlapping indices (legal, maturational, occupational, sexual, emotional and the like) employed, or on whether 'a developmental perspective... the socialization perspective is taken. 'Sub-phases in this timetable of psycho-social growth patterns... are not rigid, and both social change and individual variations must be taken into account' —not to mention regional and cultural differences. Arguably indeed, with people living longer, and also reaching puberty earlier, 'age norms for major life events have become highly elastic' by the twenty-first century. Due to generational changes, the pathway for young adults to fulfill their adult responsibilities has become less predictable. With growing changes in college education costs, living arrangements, and work and education opportunities, young adults are experiencing various life transitions in many stages of adulthood rather than one stage itself.

Some have suggested that, after ' Pre-adulthood... in the first 20 years or so... the second era, Early Adulthood, lasts from about age 17 to 45... the adult era of greatest energy and abundance and of greatest contradiction and stress.' Within that framework, 'the Early Adult Transition (17–22) is a developmental bridge between pre-adulthood and early adulthood', recognizing that 'the transition into adulthood is not a clear-cut dividing line'. One might alternatively speak of 'a Provisional Adulthood (18–30)... the initiation to First Adulthood' as following that. Alternatively, MIT has generally defined "young adulthood" as 18 to 22, although this is likely to align with the typical age range of college students.

Despite all such fluidity, there is broad agreement that it is essentially the twenties and thirties which constitute ' Early adulthood... the basis for what Levinson calls the Dream —a vision of his goals in life which provide motivation and enthusiasm for the future.'