Hard work compounds

Working longer hours means improving faster.

Learning is compounding, and anything positive that compounds is worth exploiting. Working more gives you more opportunities to test and learn, practice, evaluate, and think. All of this, done well enough, will help you improve.

At the end of the day, you're competing against the next best version of yourself. 1% better every day over 2 1/2 years, and you will be 100x better than the version of yourself that didn't do that.

Working "smarter" gets too much airtime. You should work as smart as you are capable of: that is the expectation. Then work harder. It's much easier to just work harder than it is to just work harder.

You could work too hard, but that wouldn't be smart. Pay attention to what your body and mind need: this is part of working smart. Sleep enough, eat right, take the breaks you need.

You can build the capacity to work harder. Just like building muscle, you do this by combining practice with appropriate rest, recovery, and supplementation (e.g. learning).

Finally, introspect, evaluate, and learn. Learn from others by talking to them, interviewing them, observing them. Evaluate your own progress and approach, and enlist a manager or coach or peer to help you evaluate. Learn how to improve your own self-evaluation, and seek faster feedback. Think about how you spend your time, and where you'll be in a year or five if you keep spending it this way.

There may be asymptotic returns to improvement in certain domains, and deciding when to invest your time and effort in something else is another important choice. But if you're not where you want to be--however you might assess wherever you are--then work harder.