You can die penniless with <i>way</i> less math than that.<p>The problem I have with this analysis is that -- at least with my first read-through -- it has no floor on income. It's just trying to maximize the amount of money spent during your lifetime, with the only penalty for spending early being that you don't earn interest on the money later in life.<p>The question most people want answered involves a floor to the amount of money they have to spend in the year. If I spend all my money at age 90 and manage to live to age 91, my regret isn't the 5% interest I missed out on, it's that I'm now destitute and homeless at age 91.<p>How do I maximize my expected lifetime spending while maintaining some floor on my annual spending?