I have been a software developer for the last 10 years. I have been constantly try to change jobs every 3 to 4 years but still whenever I go, I get quite comfortable and thus it hampers your future ability. The thing is if you are young then being in a comfortable job is bad for your future. You will learn but not that much which will help in your future.
PC: Pixabay.com
And that's why if you grind early in your career, the career will be long as well as you will become master in that. And that's why what I have seen that people getting into big tech companies early on their career because first of all they don't have much responsibility as well as they can devour most of their time to unskill. But when you are married, in a mid thirties, have kids at home, getting time for your self as well as for studying is hard. Even though you get the time, the your body will not allow you to concentrate for long hours.
And that's why being knowledgeable early in your career will help to shape your future career. The thing people learn late in their career being in comfortable job, you already know that. Also when you have so much experience, getting into a new tech stack is challenging. Because you have to unlearn whetever you have learned till now and thus that's a huge task. Whereas when you are young, you can actually learn, unlearn and do whatever you can.
So as a oldie, I would advise my younger self to work your ass off as much as you can early in your career and never think about comfortable job atleast first 8 years in your career.