There are certain stretches of the year when the players feel one double-bogey in the first two rounds can result in a missed cut. Players feel they have to analyze all these elements to see where they can get that half shot back. Most companies use Tour players as cornerstones for huge marketing campaigns. An Els or a Stricker adds luster to a product. To have a young player on the rise using clubs that seem to offer the average player something more is a good way to make money, which is what Cobra did with Greg Norman back in the 1980s.
Most endorsement contracts require a minimum of nine clubs to be played.
Ping, to note one exception, requires its players to use their putters, something that Robert Gamez didn't prefer to do when he switched in 1993. He hasn't won since, either. Most contracts call for the player to use the company's irons, though Taylor Made and Cobra and Callaway want players to use their drivers, too. Drivers are the industry's most profitable club, which is why Callaway, to name one, touts the success of their clubs on the world's golf tours. Callaway, however, is not so quick to reveal the vast amounts of money offered to pros to play those clubs.