Marginal analysis involves making decisions for each individual unit as opposed to an "all-or-nothing" situation. This analysis compares the marginal cost and marginal benefit of each unit. If the marginal benefit is greater than the marginal cost, the individual (or firm) will be better off and will consume that unit. If, on the other hand, the marginal cost is greater than the marginal benefit, the consumer will be worse off, so they won't consume that unit. Marginal analysis is useful in decision making because it allows the consumer to choose the best quantity that will maximize their net benefits.