This chapter explores the challenges of financing retirement and why it may be worth overriding people's behavioural traits if they do not want to work until they drop. It describes different systems for financing retirement and the risks involved. Economies across the world are facing a curious dilemma: their citizens are living ever longer as a result of medical advances, better diet and improved lifestyles, but the cost of supporting older age groups looks increasingly unaffordable. As a result, most developed countries are experiencing an ageing population. UK citizens qualify for a state pension by paying National Insurance contributions set as a proportion of their earnings from a job or self-employment. State pensions are normally financed on a pay-as-you-go basis. This means that the money paid out to today's pensioners comes from the taxes levied on today's workers, so there is a direct transfer of Gross Domestic Product (GDP) from workers to pensioners through the tax-and-benefits system.