One way to think about subscriptions is to translate them into additional-years-to-retirement. How much capital would you need to accumulate to generate enough

One way to think about subscriptions is to translate them into additional-years-to-retirement. How much capital would you need to accumulate to generate enough investment income to pay for the recurring expense? How many years of extra work would you need to accumulate that amount of extra capital from savings? For example: suppose we're considering a recurring expense of $10 / month = $120 / year. How much capital K would we need to generate income to pay for this expense? Assuming a 4% real annual return on invested capital [+], we'd need K = $120/0.04 = $3k. How many years of work does it take to accumulate savings of $K capital to invest? Assume a median US individual annual income of around $30k and an optimistic savings rate of 5%. Savings per year = $30k * 0.05 = $1.5k / year. Years of work required to accumulate enough capital to cover a $10 / month recurring expense: $3k / ($1.5k / year) = 2 years [#]. In this scenario, avoiding the $10 / month recurring expense is roughly equivalent to retiring 2 years earlier than otherwise. [+] i.e. the long-run annual real return from investing 100% into the stock market given current market conditions [#] this over-estimates the amount of work required by a few percent as it neglects that we can start investing our savings while we are accumulating it