PGA Tour players and other pro golfers depend on their caddies for yardages, local knowledge, the wind direction, sometimes alignment, cleaning golf balls, raking bunkers and so much more on the golf course.
In turn, caddies rely on their players to get paid, and what caddies earn is almost entirely dependent upon how much their players earn on the golf course.
Since PGA Tour players and other professional golfers are considered independent contractors, they're responsible for hiring and paying their caddies. A standard-issue deal between a pro golfer and caddie pays a looper 5 percent of most earnings on top of a small weekly base salary ($1,000-$2,000 on the PGA Tour). However, when their player finishes in the top 10 at a tournament, the caddie usually earns about 7 percent of the money. If their player wins, then the caddie earns about 10 percent of the first-place prize money.
At a major championship where the purse is $10 million, the player would win $1.8 million for the championship. The caddie would then get $180,000 for the week.
Some top-tier players have different relationships with their players, with a higher minimum salary. However, if a caddie works with a player for 20-30 events per season, a caddie will earn a minimum of $20,000-$30,000 per season, and that's assuming a player makes zero cuts all year.
However, no matter what, the caddies are also independent contractors that can be hired and fired pretty much at any time. This means caddies are mostly responsible for their own travel to and from events, lodging at tournaments, health insurance and more. Caddies have formed an organization called the Association of Professional Tour Caddies to help caddies earn more money from appearances and band together for group discounts on things like health insurance, as well working with the professional tours to improve caddies' working conditions, ranging from better access on tournament sites to improved food.