A typical round of golf consists of playing 18 holes in a set order determined by the course layout, with each hole played once. Groups usually have 1–4 players, and an 18-hole round takes about four hours. Each hole starts with a shot from the teeing ground, where the ball may be placed on a tee. The first shot, called a 'drive,' is usually made with a driver for long distances. Players continue to strike the ball with various clubs (woods, irons, wedges) as needed, aiming to reach the green and then putt the ball into the hole in as few strokes as possible. Obstacles such as rough, doglegs, bunkers, and water hazards may impede play. In stroke play, every stroke is counted until the ball is holed, while in match play, players may concede holes. The total course length can exceed 7,000 yards, and players may walk or use golf carts. Caddies may assist at higher levels of play. Informal rules may allow players to pick up after a triple bogey to speed play, and some competitions set a maximum score per hole.