Simply put, a golf shaft is measured from the top of the shaft to the point where the shaft meets the ground. How long this shaft should be depends on the individual. Factors include genders, height, arm length, swing speed, handicap and age. The best way to determine what size shafts you use is to have your swing analyzed by a professional who can determine exactly what length best suits your game.
Difficulty: Moderately Challenging
Realize that the club has to be an extension of your arms and that the club should remain at the same angle as your arms when you are addressing the ball. If you have to stand more than 24 inches away from the ball at address, and you are forced to hold the club at an angle, then the club is too long. If you feel cramped when you are holding the club, and you are too close to the ball at address, then your club is too short.
Figure out your swing speed. Older golfers tend to lose speed in their swing over the years. As a result, to generate more power, the older golfer may need slightly longer clubs. That golfer has to realize that the swing path will have to evolve if he is using longer clubs.
Determine the size of the shaft you should use by the length of your arms. A 5-foot-10 male golfer will normally use a standard 42-inch shaft on his driver if his arm length is proportionate to his height. Interestingly, a 6-foot-6 golfer will also use a 42-inch shaft if his arms are also in proportion. However, a golfer will need longer clubs if his arms are shorter than normal, and shorter clubs if his arms are longer than normal.
Realize that standard 42-inch shafts are fine for about 80 percent of all golfers, but that any individual may be different. You may feel more comfortable with longer clubs that you choke down on 1 or 2 inches. You may want shorter clubs because you feel more comfortable standing closer to the ball. In the end, you have to go with the clubs that you feel most comfortable with.
Try out a set of clubs of the length you are considering buying before you make your purchase. Many pro shops or golf specialty shops will have a practice tee to hit the ball from in order to let the prospective buyer familiarize himself with before making the purchase.
Tips & Warnings
Take the time to get measured if you are buying new clubs. Don't just buy the first set off the rack that looks good to you.