Rook move after Kingside Castling

Hi all,

I have a question related to casting on the king's side. I noticed several players move the Rook in horizontal of one cell after casting. For example, in the World Championship FIDE Nepo vs Carlsen, the Spanish game has been played several times.

If you looked here, you notice at move 6 Nepo move Re1:

https://www.chess.com/a/2VfYL13ypBAJn

I am wondering if this is a best practice move that people do after Castling. Is it valid for whatever opening or only the Spanish line? What are the pros and cons of this move?
Thank you in advance for your reply.

There are no general principles that tell you where to put your rooks. Every position is different.

In this particular opening, Re1 defends the e4 pawn. Plus: if and when the e-file opens up, the rook wants to be there.

In other positions, that rook may be better on d1, or c1, or even f1.

The most important thing is: thinking about opening lines is not very profitable. There are many more things that help you much more: solving puzzles, watcing videos, reading a chess book.

Thank you very much for reply.

Yes, I know. I do it every day with a precise plan.

It's clear to me that, especially for beginners, thinking too much about the opening is not so useful. It's better to know the opening principles and just a few key openings.

The reason for my question is only curiosity because I noticed it several times.