Most people overestimate their ability to hit the golf ball. They think they can hit it longer than they actually do. This is factual, not to mention this is the number one mistake I often see during a playing lesson or in pro-am tournaments.
Part of the problem is that few amateurs know how far the ball goes with each club. A professional measures the carry he will get with a particular club. An amateur measures everything!
This can have a huge effect on your shot’s outcome. If a green has a hazard or trouble in front, the pro knows what club he needs to carry the ball to the putting surface. The amateur is more inclined to underclub. For example, you might be able to hit a 5 wood 200 yards total, but that might be 175 yards carry and 25 yards roll. To get your ball on the green you may need to hit as much as a 3 wood. Trouble is, you’ll probably hit the 5 wood, come up short and be left with a shot from within the trouble. It is an ego thing!
The solution is to know how far you hit the ball with each club, both through the air and on the ground.
Does this mean you have to measure every club? NO! Three is enough. Measure an 8 iron, a 5 iron and a fairway wood in calm conditions. You can work every shot off of those yardages. Use them as the starting points, and calculate the rest accordingly.
Take your measurements in calm conditions and remember to also apply the possible influences of wind as you are on the course playing.