The Defining Decade: Why Your Twenties Matter and How to Make the Most of Them Now

For people who are reading this book in their 30s or 40s, it can be very hard-hitting.

The author describes that the majority of the key decisions regarding our career and relationships happen in our 20s which defines our trajectory for the future.

Some studies also show that about two-thirds of lifetime wage growth happens in the first ten years of our career. i.e our 20s

I prefer this book because the author is a Clinical Psychologist Meg Jay who specializes in adult development and whose actual job is to work with twentysomething day-to-day problems.

Following are some of the chapters that I resonate with most.

1. Work

Twentysomethings are more educated than ever before, but a smaller percentage find work after college. The ongoing trend of the 30s in the new 20s, most of the twentysomething move all the major life decisions for later and try to avoid major commitment in their 20s.

They will often say “We have a lot of time to do that later. Let me enjoy my 20s first because I am not going to get this time back”

And that’s true, we won’t be getting this time back, and it seems pretty obvious in the 20s but the actual realization happens in midlife where our twentysomething choices cannot be undone.

Instead of avoiding things for later, the author suggests investing 20s to build Identity capital i.e our collection of personal assets. Invest 20s time to grow your People and Professional skills. Identity capital is how we build ourselves– bit by bit over time

2. Weak Ties.

Weak ties are the people we have met or are connected to somehow, but do not currently know well. New things almost always come from outside your inner circle. For example, one of your colleagues is referring you for a job.

Of course, strong ties like school/college friends also plays the important role in your early life, however, from my personal experience most of the major life/work event was triggered by the people outside my circle. I will be always thankful to them.

3. Love

I will just directly quote from the book

“Today’s twentysomethings spend more time single than any generation in history. It seems like it’s easier and more realistic to plan our careers and financial stability than to plan our marriages and babies. Besides, like with work, good relationships don’t just appear when we’re ready. It may take a few thoughtful tries before we know what love and commitment really are.”

As with work, it’s better to try things early, because as we grow we become more resistant to change ourselves for others.

“You’ll never know with complete certainty. That’s why marriage is a commitment, not a guarantee.”

4. The Brain and the body

Some studies show that our brain’s frontal lobe which is responsible for our reasoning and judgment will be still under development in our 20s.

Because the frontal lobe is still in developing mode, we are constantly bombarded with questions in our heads like Whom to marry? What to work? and Where to live?

The frontal lobe is also responsible to makes us forward thinkers. i.e we just don’t think in terms of the present but also in terms of the future.

Forward-thinking is not like school where we solve a problem and with correct answers within a given time limit. It’s about making decisions in the present which helps in the future or planning things ahead of time to deal with uncertain situations (which happens all the time).

5. Do the Math

In the final part of the book, the author explains how the clock is ticking for the 20s. Because Again and again, twentysomethings hear they have infinite time for the dreaded adult things but so little time for the purportedly good stuff. This makes living in the present easy. It’s connecting the present with the future that takes work.


After reading this book some might feel overwhelmed or stressed or maybe be it can be a wake-up call for some p.

But remember life just does not end in the 20s. Many people have achieved great things after their 20s. From my point of view, the book is emphasizing on to not wasting your 20s. Because there few key decisions and commitments happen in yours 20s which are very hard to revert later in your 40s or 50s. So Focus on that.

For me, The one-line summary would be

Work, Relationships, and Building Family are all equally important. Take responsibility and be committed to it. The skill is to find the right balance between them.

So as long as you donโ€™t waste your life in your 20s, youโ€™re on the right track. Not everyone can end up being successful but at least you have to try to optimize that chance with the time you have.

You can get the book from amazon here. Below is her famous ted talk.

Highlights quotes

  1. Hope is a good breakfast but a bad supper.
  2. The one thing I have learned is that you can’t think your way through life. The only way to figure out what to do is to do something.
  3. When we make choices, we open ourselves up to hard work and failure and heartbreak, so sometimes it feels easier not to know, not to choose, and not to do.
  4. For many, Facebook is less about looking up friends than it is about looking at friends. How our partners look is more important than how they act, the race to get married is on.
  5. Adult life is built not out of eating, praying, and loving but out of person, place, and thing: who we are with, where we live, and what we do for a living.
  6. The most difficult thing to cure is the patient’s attempt at self-cure.
  7. Personality is not about what we have done or even about what we like. It is about how we are in the world, and this infuses everything we do.
  8. Friends can form a culture of criticism where differences are seen as deficiencies.
  9. The art of being wise is knowing what to overlook.
  10. Inaction breeds fear and doubt. Action breeds confidence and courage. If you want to conquer fear, do not sit home and think about it. Go out and get busy.
  11. Confidence doesn’t come from the inside out. It moves from the outside in. People feel less anxious and more confident on the inside when they can point to things they have done well on the outside.
  12. People of all ages and walks of life discount the future, favoring the rewards of today over the rewards of tomorrow.
  13. There is a big difference between having a life in your thirties and starting a life in your thirties.

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