If you study web development now, will you need to change your code a lot in 10 years time?

Hi :)

I was just curious whether if you study web development now (and aim to master the core/essentials of HTML, CSS, JS, PHP, and MYSQL, namely) and create websites with those technologies combined, how much will you have to change re the code structure and design, in about a decade's time?

In other words, with programming being something that changes ever so often, I would like to invest my time in something that I am passionate about as well as something that won't be a great loss if I leave it off for some time.

For example, if you were to master the core principals of any one of those techs I mentioned up there within the next few months/years, what would it take to pick it up again if you left it off for some years and found that the language has changed plenty?

My father was once a PHP & MySQL expert around 14 years ago, and coming back to it now he finds the changes absolutely frustrating.