If you start with $1000 , and you can figure out a way to 2x ROI that injection during a 'cycle', then you have $2000. So, what if you can 2x ROI that amount for the next cycle? How many 2x ROI cycles do you need to get through, to hit a reasonable retirement level? (Note: this is a study of financial goals, not of exact ROI returns. The purpose is to help develop goals for yourself, so you can better analyze how you're coming as you work forward through any level of ROI.)