Can you change a golf club during a round?

Answer 1

You can change Golf balls in a tournament. As long it is on different holes or the ball is unfit for play, (like if it hit the cart path and was scratched.) But if it was unfit for play you must tell your opponent.

Answer 2

No, the ball you start a hole with is the ball you finish the hole with. Unless it is visibly cut or out of shape, in this case you may replace the ball (if agreed with official or playing partner) for the same brand and model of ball.

You can change your ball before you start a new hole, but never during play.

Answer 3

Yes, on top of each other.