Some struggle with medical issues - like insomnia - that make sleep hard. But for many of us, the quantity and quality of sleep come down to a matter of choice. Still, only a few enterprising economists have looked closely at this, and generally, those have assumed that we choose our hours of sleep optimally.

If a man walks in the woods for love of them half of each day, he is in danger of being regarded as a loafer. But if he spends his days as a speculator, shearing off those woods and making the earth bald before her time, he is deemed an industrious and enterprising citizen.

If a man walks in the woods for love of them half of each day he is in danger of being regarded as a loafer. But if he spends his days as a speculator shearing off those woods and making the earth bald before her time he is deemed an industrious and enterprising citizen.