Spin is defined as the rate of rotation of the golf ball when hit by a club. Spin rate is expressed in RPM and is measured about the golf ball's Axis of Rotation, regardless of the orientation of that axis.
In a round of golf, every shot you hit is going to have backspin. The backspin is driven by how you're delivering the club to the ball but also the type of club you're using. For instance, you’ll experience less spin with your low lofted driver and more spin with your high lofted wedges. The ability to generate spin on wedge shots into the green, bunker shots, and pitch shots out of the rough is important for you to be able to control the golf ball and get the result you’re looking for.
Spin is also a critical factor when you're hitting iron shots. Spin enables you to evaluate the peak height and the angle of descent of your shot as well as the reaction your golf ball has when it lands on the green. To get it close to the hole, you need to know and understand your spin rates.
It’s all about getting the appropriate amount of spin on a variety of shots. If you're not generating enough spin on an iron approach shot it may go further than expected and then release out too much when it hits the green. On a golf shot that spins too much, take for example a seven iron approach shot, the golf ball could balloon up into the air costing you distance. Ultimately, if your golf ball falls even just five yards short of the green it could be the difference between a birdie putt and being plugged in a front bunker.
When you have the right amount of spin for your game, you are going to be able to use club selection and technique to control all the different types of shots that you hit.