A hole in one is the Holy Grail for many golfers, with just one in their life being cause for great celebration and a sense of accomplishment. After holing out from the tee box, there are rules a player should keep in mind when determining whether the shot is in fact a hole in one, as well as how to act in the wake of a successful ace.
Just because you have struck a ball from the tee box into the hole does not mean it's time to celebrate. While holing out is always an accomplishment to be proud of, the shot is not always a hole in one. If you're playing a second ball from the tee because your first went into a water hazard or out of bounds, it will not be recognized as official; holing the ball under those circumstances results in a 3.
Legal Second Ball Aces
It is not impossible to hole a second ball and have it count as a hole in one. If you take a swing out of turn in a match play pairing, your opponent has the option to cancel the shot and have you hit again when it is your turn. If this second ball is holed, it's a hole in one. If your original tee ball strikes an unnatural obstacle, like a power line, local rules can dictate a free replay. You can also score an ace with your second tee shot if your first strikes a cart path and breaks into multiple pieces.
Other Ball Movements
A ball at rest can still end up being moved because of acts of nature outside the control of the player that struck the ball, such as interference by an animal or a powerful gust of wind that causes the ball to roll. Should a player strike a ball that ends up near the hole and it is then blown into the hole by the wind, it's a hole in one. But if an animal moves the ball, it must be replaced with no penalty as near as possible to its original position.
After a Hole in One
Beyond the USGA rules, there are traditions that are followed by many golfers concerning a hole in one. The ball involved should not be used again. This ensures it won't be lost and that the last shot struck with it will have led to a hole in one. You then have the option of having the ball used in a display or trophy marking the occasion. And should the round end with a stop at the 19th hole, it's customary for the player who made the hole in one to buy a round of drinks for the group.