About 4.5 to 5 nine hole rounds per ball, between 110 and 120 hits with balls of the type you use. If you shoot, let's say a 36 on average for 9 holes with 13 putts, you will put 23 hits on your ball. Putts do not count as ball hits unless you are on the fringe. In the SEARCH box to the right on this page, if you type in "ball durability chart" it will take you to forum posts with charts of many different balls and break down their cost per nine and so forth. :-)