The approach of “save a percentage of your income” is a staple of retirement planning. While much debate exists about the exact ideal percentage, the concept is relatively straightforward – have savings to be one of the slices of your income pie, ideally automate the process with an ongoing percentage of your income that always gets saved first, and you’ll be well on your way to retirement.
Yet the reality is that saving something like 10% of your income also implicitly means you’re spending the other 90%, and continuing to do so over time means you'll also be saving (only) 10% and implicitly increasing your standard of living by 90% of ever raise you receive in the future. As a result, your standard of living rises as fast as your retirement savings, which means the amount needed to reach retirement gets larger and larger given the retirement costs to be supported, and in the end it’s surprisingly difficult to ever reach retirement at all as the goal forever outpaces the savings to reach it!
By contrast, an alternative approach is to try to spend “just” 50% of each pay raise you receive in the future (implicitly saving the other 50%). The end result of such an approach is that increases in the standard of living are more controlled and rise far more slowly, savings grow exponentially (to more than 20% of income within just a decade, even from a starting point of 0%!), and you can even retire early… all while feeling like your lifestyle is steadily rising as you’re still committed to spending more every year, just not increasing as rapidly as saving 10% of your income (and spending the rest)!