- will depends of your particular situation and based on your risk tolerance (inner priorities) but I would strongly suggest learning (and to be more precise your learning rate, learn how to learn and unlearn faster over time)

- I'd suggest to maximize healthy habits based on having a deeper understanding of your own body, make it so good and so custom that most likely with only work for you, the compound effect in months years or even decades is notable

- avoid lifestyle inflation (could overlap your second question) polish your personal finance knowledge and try to adapt it to your generation ("modern" vs "classic"), as example don't think that own > rent as default, question the status quo, question the principles on which that kind of statement relies and do the same for similar situations

If physically possible, marry and bear three children, raise them to be productive members of society.

Within reason, here is what I suggest.... learn to cook so you save money. Avoid eating out too much and developing that habit. exercise Dont drink alcohol nor smoke. develop your executive skills for work and social. This is on top of any technical skills required for your career Save money, park as much as possible into your 401/IRA. Contribute to the community. Live close to work so you do not spend all your time commuting. Its okay to pick up cheap things at the thrift store. Never get a storage locker.

Advice at the end of the post. See if you can benefit from my crazy quilt career.

When I was in my 20’s, I started out in grad school, but a physics course overwhelmed me. That so happened to be draft era, and my lucky number was 17, so I spent four years in the Coast Guard. (Volunteered. I don’t think they drafted.) and then got started in aerospace.

Looking back, I don’t think that an academic career would have worked out. The fit honestly wasn’t there. How do I know? Well, several aerospace jobs later, I went to work on the staff at Cal Berkeley, as the computer systems manager, and I got a deep look over the fence. I was more comfortable solving small problems that directly impacted people.

One thing I do remember from those 20-ish days is that I built up a small network and we made a few bucks referring each other for jobs. And looking back, it continued, though not always with great results. (Oh, those repeated interviews at the fruit company didn’t pay off) but I see the pattern in retrospect. It opened many doors.

And the oddest thing is that when aerospace was laying off, my wife and I visited a coffee shop and found a newspaper lying about with an ad for that Berkeley position. Newspaper ad? Well, that says how old I am. I found my wife via an ad in a personals newsletter “Trellis Singles” in the valley.

But do make friends, make connections, and ask the universe for unusual opportunities. I was a Woz kind of person but never found the matching “Jobs”. One guy came close, but he trashed his personal life. So long.

Cultivate some lasting hobbies and habits that will give you enjoyment throughout life. Mine were (besides pioneer microcomputers) photography and classical piano, and at my (redacted) age, they are constant delights. Raining? Look for a rainbow. I got one the other evening. And the 50 year old Hasselblad still works fine (needed a minor repair) Not bad. But I am lazy lately.

You will find that taking quality photos in your 20’s will make great memories later on. I married at 36, no less, and took wonderful photos of my daughter growing up. And the stumbling piano practice then, and through the years, suddenly got better when my sight reading took a major leap not so long ago.

Never put off doing a good deed. The opportunity may never come again. Build foundations. And that includes the math skills that somehow got “unwired” from my brain (college was a highly stressful time, late 60’s) I was a jack of all trades person, and each job change built on the previous one, but also demanded going beyond, so learn new stuff all the time.