Changing your golf ball
According to the rules of golf etiquette, may you change your golf ball during play?
A golf ball may of course also be changed during the round. However, this may only be done after finishing a hole or before starting a new one. Unless the ball is damaged, in which case it may also be changed during a hole. Whenever a new ball is put into play, however, your playing partners or the marker should be informed. Damaged balls should first be confirmed as such by the marker.
In accordance with the rules of golf etiquette, professional golfers may change balls just like amateurs. However, a One Ball Rule usually applies here. This states that during a tournament round the ball played must always be the same brand, model and compression, i.e. the ball may only differ in its numbering or in a marking applied by the player.