A frequently asked question about the rules of golf is whether a player can change balls mid-round or even mid-hole due to cuts, ball performance, or other reasons. To clarify, here's the USGA's rule:

Rule 15-1

Changing balls during a hole or a stipulated round

Question: Can a player change balls during play of a hole or a stipulated round? If substitution is permitted, can they change to a different brand or type of ball?

Answer: Rules 15-1 and 15-2 state that a player must complete a hole with the same ball with which he started it, unless a rule permits him to substitute it. However, he may change balls between the play of two holes.

Rules 26-1 (Water Hazard Rule), 27-1 (Ball Lost or Out of Bounds), and 28 (Ball Unplayable) allow the player to substitute a ball. Rule 5-3 also allows this if the original ball becomes unplayable during the hole. Other rules, such as Rules 18, 24, and 25-1 , only allow a substituted ball if the original ball is not immediately recoverable.

It's important to note that Rule 16-1b , which allows lifting a ball on the putting green, does not allow it to be substituted . This prevents a player from switching to a "special putting ball."

If a player changes balls without permission, he or she will incur a general penalty ( loss of hole in match play or two penalty strokes in stroke play ). For example, if a player takes free relief under Rule 25-1 (Ground Under Repair) , he or she must do so with the original ball (unless it is not recoverable). If he or she substitutes a ball without permission and makes a stroke with it, he or she will incur the appropriate penalty.

Where a change is permitted, the player may substitute a ball of another make or type , unless the Committee has applied the One Ball Rule (see Appendix I, Part C, Section 1c). This condition usually applies only in professional or high-level amateur tournaments, but is not common in club competitions .