There are three things you must consider when choosing a golf shaft: composition, flex (the amount it will bend when you swing the club), and length. Together, they are critical to the selection of a shaft that will match your abilities and style of play. If you make the right choice, you will see almost immediate improvement in your game.
Choose between shafts made of steel or graphite. Graphite shafts are lighter but more expensive. If you have a relatively slow swing, or if you are just beginning to play, these might be the shafts for you. They are easier to hit and tend to increase the speed of your swing, which will result in greater distance. If you are a seasoned player with a low handicap, you will appreciate the greater feel of shots made with steel shafts.
Pick the correct flex of shafts. Both graphite and steel shafts come in five different flexes: ladies, seniors, regular, stiff and extra-stiff. If you have a professional club fitter who is helping you choose the right shaft flex, he should have a machine that will analyze you swing. From that data, he will recommend a flex. Otherwise, base your selection on how far your drive carries. If your ball travels about 225 yards, you should probably have regular shafts. Any less and you should choose either ladies or seniors, because they bend more and will help you swing with minimum effort. Stiff shafts bend only a little and are for players who regularly pound the ball from 250 to 275 yards. Extra-stiff shafts are reserved for professionals and players who hit a mile.
Make sure your shafts are the correct length for your body and swing. For instance, you may be shorter than average, but since you also have shorter arms, it may mean that you do not need shorter shafts. Use the standard shaft lengths by club mentioned in the website cited in Additional Resources as a starting point. It is correct for about 85 percent of all golfers. Make adjustments according to your height and preference.
Vary the shafts depending on what you are emphasizing. You are not obligated to have all the same type of shafts. For example, you may want a driver with both a graphite shaft and a titanium clubhead to get more distance, but you prefer your irons to have steel shafts for the feel.