Whether those who claim benefits should face a work requirement has been an issue of long-standing social concern. Important examples of schemes which require work are the Californian workfare program, Indian food security schemes and the English Poor Law of 1834. We present two arguments for demanding work for benefits: first, a work requirement can scree the truly needy from those who are not in need of support and second, it can provide incentives for people to invest in skills which enable them to avoid poverty. In the context of a simple model of a target population with two ability types we find conditions under which a work requirement reduces the costs of poor relief, and those when it does not. We concentrate on a case when work done in return for benefits has no social value, showing that even if this is true, work requirements may be a valuable policy tool.