I came across this concept a while back in a Mark Manson video. Manson is an author and has some interesting ideas. Not someone I actively follow but have seen and read some of his stuff in the past and much is sound. Which brings us to this particular piece of content and my thoughts on it...
That being, the 4 stages of life as he lays out. Perhaps this is a common framework, I have no idea, but it certainly makes a lot of sense and we can break it down a bit here.
Stage 1: Mimicry
This could be the early stage of life and of any endeavour. You know nothing, and you're just imitating what's around you. You may not know if something's good or bad but all you've got is copying the other's example.
This obviously happens with babies and also teenagers (and others) in a slightly different manner. With the baby that's all they've got to go on, with bigger 'kids' it's more about fitting in with the group (including those pretending not to care and not fit into any group, which in itself is an identity shared by others, aka a group).
Each time you start something new you are in this phase. As a baby, you're just going on instinct, as an adult it's more intentional but you may have to get started this way before moving on to the next phase.
Stage 2: Exploration
This is a biggie and forms the next part of your life, or section of experience. Exploring, seeing what's out there, and getting plenty of data. You'll use that data in future phases and this will never fully go away but there are more pronounced times of your life when it takes place.
This is finding out who you are and what you're about. Self-discovery. Your place in the world. This can be seeing the different places, trying ways of dressing, religion, dating, travelling, different jobs/careers etc.
This can be a lot of fun and interesting. It can also cause angst and can't go on indefinitely (that's up for debate of course and it will always factor in wherever you are). Once you've had your fill of this...
Stage 3: Commitment
As it says on the tin: you commit. You decide on a course of action, place or person and that's it (for now anyway). The dating phase is over and now you 'settle down', perhaps marry. You decide on a place to live, perhaps buy over rent. The job or business is fairly set and this is your life now. Both potentially exciting and depressing so you need to get this right.
Sure, you might not want to be a 'Peter Pan' but you don't want to be stuck in undesirable circumctances either. That's the quandary. Always an element of risk but a very rich life awaits.
This of course may not be forever. Divorces happen, jobs end and sometimes a place has served its time. There may be things that you're always commited to (children for example in one way or another) but everything is in a state of flux, people and situations change and that's fine. Perhaps some more exploring before coming back here?
Stage 4: Legacy
You're getting old now. Not really but perhaps that last quarter of life... the autumn and winter years. Not a young buck and it will all end one day. Now what? You're not building for yourself so much any more, but perhaps for others in your family, community and beyond. Maybe you want your name to stand for something, or your work and ideas to live on. This is where you stake your stake - "I woz 'ere".
Getting your affairs in order. Doesn't have to feel bad, it can all be very positive and now you can slow down a bit, maybe the body isn't what it was so the mental or spiritual side is getting its turn.
You're not chasing the yanky dollar or her/him and you're looking towards your future as it stands. Time to pass the baton, leave things better than you found it and leave a strong legacy (if that's what you want).
In a life sense you could say that these phases can can be around 20 years each. The out and out mimicry will be for the little'ns but may go on further for some. Exploration could really go on from young teens into the 30s as a general rule, commitment in your 40s and looking towards legacy in your 60s. Of course there aren't any rules and they vary and go in cycles.
You could well be circling through these phases all the time, whether that be decades or a matter of days. And it obviously varies for different people at different times.
An interesting way of looking at things and it does appear that's the way it goes...
So where are you with it all?