It is well believed that learning and memory is one of the functions of sleep. Not only does the sleep after learning aid memory consolidation, but enough sleep before learning is necessary for memory formation. Due to the net increase in synaptic strength, waking plasticity has a cost in terms of energy requirements, space requirements, and progressively saturates the capacity to learning. The review will focus on the role of sleep which is to downscale synaptic strength to a baseline level that is beneficial for learning and memory.