This balance of spending today and the risk of outliving assets presents a challenge when both longevity and asset returns are unknown. Asset returns, particularly immediately before and just after retirement, can have a big impact on the amount a retiree is able to safely spend each year. Sustaining income over a long and healthy life also puts pressure on an investment portfolio as assets are gradually spent down. Managing assets to create income becomes a significant challenge for the increasing percentage of Americans who suffer from dementia in old age. A retiree can reduce all of these risks through the purchase today of a guaranteed income stream in the future.