You don't want to miss hunting opportunities, so teaching your hunting dog to quarter is a great idea, and starting your dog performing this behavior from the start, before he develops the habit of traveling in a straight line, is ideal. Some dogs, notably spaniels, have been bred for generations to naturally perform this behavior, by scenting and moving into the wind and traveling in a zigzag pattern to find scent and cover the ground around their handlers. Although other dogs can be trained to quarter, a dog that is naturally inclined to perform this behavior will be much easier to train.
Quartering allows you and your dog to thoroughly cover the ground around you. Small prey can easily be concealed in tall grass or brush only a few feet from you. Having a dog that quarters and scents the air back and forth, from side to side in a zigzag pattern, increases your likelihood of locating hidden game, resulting in increased hunting opportunities.
Ideally, you should start your dog hunting from a very young age, using a quartering pattern so you do not have to break your dog of the habit of rushing out in front in a straight line. Dogs are usually taught to move back and forth, ranging in front of and to the side of handlers, and to turn and change direction, crossing in front of handlers in response to a signal, usually a whistle. You will want your dog to stay in range of your shotgun so that any quarry he flushes can be shot. An added bonus to teaching your dog quartering is that it teaches your dog to range close to you while hunting, preventing your dog from becoming separated from you and potentially getting lost.