Work backward from success/failure

Fix a finished outcome first, stated concretely, then walk the chain in reverse: what had to happen right before that, and right before that. Each step back names one requirement, so branches that lead nowhere never get explored.

Fix a finished outcome first, stated concretely, then walk the chain in reverse: what had to happen right before that, and right before that. Each step back names one requirement, so branches that lead nowhere never get explored.

Example

You fix the endpoint: age 65, $80,000 a year, no mortgage. Working back, at 60 the portfolio must hold roughly $2 million; at 50, $900,000; which means saving $2,400 a month starting now, not the $1,100 you save today.