I'll go out on a limb and say that even normal retirement planning (50 years into the future) is a Maserati Problem.
Everybody that makes very long-term projections about money -- whether it's the gloomy "interest on $4m won't last 40 years" variety to the rosy "save $300 a month and the compound interest will make you a millionaire in 50 years" -- commits the same error: They neglect the fact that wars, revolutions, devaluations, confiscations, and other economic disasters have wiped out all savings at frequent points throughout history.
There should be some trillionaires walking around whose ancestors started saving in the Renaissance when modern banking began -- but there aren't.
So if you're talking time scales of 50 years, there is significant probability that your carefully calculated spending or savings plan is self deceit.