Bear spray should be sprayed for a minimum of 6 seconds at a distance of at least 25 feet from an attacking bear. This allows the spray to create a wide barrier between the person and bear, giving the spray time to affect the bear's senses before it reaches its target. A longer spray duration is recommended to ensure protection in situations with multiple bears, repeated charges, defending others, exceptionally aggressive bears, or adverse weather conditions. It is important to carry bear spray for self defense when in areas with potential bear encounters.