i'm not completely sure what you mean, but here goes, for years I played Kings Gambit and Sicilian whenever i could, obviously depending on how my oppenent played there would be lots of variations, I was just trying to narrow it down so I would be more comfortable.
E-L
It sometimes happens that you want transpose into a different opening in order to avoid particular openings if you know you have problems with them.
For example, I play 1. d4, but have difficulty playing against the Benko gambit. So if my opponent plays the Benko, I might transpose to a variation of the Sicilian (which is a 1. e4 opening) that I am familiar with because I play the black side of it. This probably isn't the right thing to do, but I don't want to invest the time into opening study that I should.
since i'm new trought the game and i litteraly have not seen everything. i am testing , testing, testing, testing, testing and testing.
it's great to have theories about how good playing this or that can be, it's helpful to help you finding new things that you can use in a game.
i believe the best way to see if a strategie you tought about trought an opening is to test it with many players, if you lose 10 games using it, consider it as a bad strategy, if you win games, or often have material/positional advantage after certain things you do, or make your opponet think for a long time , consider it as something that could sometime work.
But you can not evaluate or invent new openings strategies if you know nothing about basic openings theories, they work out togheter.
Is it common practice whether playing white or black to change your opening strategy in a game or do most people stick with the same idea throughout no matter what their opponent plays? For example switch from English opening to something else entirely, not a variation.