Different golf clubs produce different results. This is why a player is allowed to carry up to 14 different clubs in his bag. The three major factors in deciding which club to choose for any given shot is - height, distance and/or accuracy.
The longest clubs in the bag are the woods. Yet they are the least accurate. The driver, or big dog, is the ideal club for smashing off the tee on long holes to get as far down the fairway as you can. Although it is the club which produces the greatest length, if hit slightly wrong, it can produce a viscous hook (sending the ball wildly left), or a violent slice (sending the ball even more wildly right). And this usually means producing a ball which is unplayable or lost. Hit correctly, and one gets a great deal of satisfaction resulting in tremendous length and an easier second shot.
The other woods, known as fairway woods, are clubs used from the fairway, also producing greater length and more risk if hit improperly. These days there are 3, 5, 7 and 9 woods. The lower the number, the farther the ball will travel. While at the same time, the higher the number, the higher the ball will get in the air.
To give an example, if I am in the middle of the fairway with no obstacles in the way and say, in excess of 200 yards to the green - I would be inclined to take my 3 wood and bash it up the middle of the fairway hoping to find the green. If I keep it straight, I'll have a good chance. But say I'm a bit out of position and need to get over a group of trees on my way to the green still, 200 yards away. I cannot hit my nine wood 200 yards, but I can get it 80 feet up in the air quite quickly. So I may sacrifice some distance in order to get height to clear the obstacle and keep the ball in play.
It's the same for irons. Irons basically range from a three iron to a nine iron. A three iron produces the greatest length, lower flight path, but more difficult to hit. A nine iron goes very high, shorter in distance, but easier to keep straight.
Most golfers I know have the clubs sectioned in 10 yard increments. Personally, my range is: 9 iron 110-120 yards. 8 iron 120-130yards. 7 iron 130-140 yards. And so until I get to my 4 iron which I plan to hit 160-170. Over 170 yards and I go to my woods.
There are also the very useful wedges. Some people opt to carry four or five wedges, varying in height and distanced produced. I carry the two basic wedges, pitching and sand wedges. My pitching wedge is good up to 100 yards and the sand wedge up to 70 yards. But more often than not, I'm not hitting these wedges at full force. These clubs are for when you are close to the green and require a feel of touch for the shot you wish to produce with greater accuracy.
I use the pitching wedge when I want to land the ball on a specific spot on the green and let it run out to the hole. And I use the sand wedge when I want to put it close to the pin and have it stop quickly.
The beauty have having these different clubs is that you can use the same swing but produce different results. I hit my four iron the same way I swing for an eight iron. Yet, I can produce up to a 50 yard difference, with accuracy.