Performance to change localScale, check value or just update?

I want to flip a character depending on where he looks. Which of these three are most effective, or are they equal? flipChar is a float of -1 or 1.

Consider this is done on several on screen characters continuously.

 // Set it each frame
 character.localScale = new Vector3(flipChar, 1, 1);

 // Check if the value has changed, then set it
 if (character.localScale.x != flipChar) character.localScale = new Vector3(flipChar, 1, 1);

 // Store a value in a float, and check if that has changed
 if (lastFlipChar != flipChar) {
     character.localScale = new Vector3(flipChar, 1, 1);
     lastFlipChar = flipChar;
 }