1. Some financial advisers view the golden ratio 4 1+x5 ~ 1.618 as an important number when determining how long to hold onto an investment. I swear I am not kidding, for example: Investopedia. Suppose you want to derive something like the "Rule of 70" but not for doubling time, but rather for the amount of ime it takes until your initial investment C in a stock reaches the amount WC, at which point you should sell. I reiterate that this is absolutely a real thing: Smithsonian Magazine. Compare the Rule of 48 and the "Rule of 50 as an approximation for this time; when would one be better than the other? 1. Some financial advisers view the golden ratio 4 1+x5 ~ 1.618 as an important number when determining how long to hold onto an investment. I swear I am not kidding, for example: Investopedia. Suppose you want to derive something like the "Rule of 70" but not for doubling time, but rather for the amount of ime it takes until your initial investment C in a stock reaches the amount WC, at which point you should sell. I reiterate that this is absolutely a real thing: Smithsonian Magazine. Compare the Rule of 48 and the "Rule of 50 as an approximation for this time; when would one be better than the other