FIRE's core principle of spending little even when you have an increased income fosters a disciplined mindset and cultivates a strong financial foundation. It enables individuals to save as much as possible for the future, ultimately leading to a more fulfilling and prosperous life.
How much to save also depends on how you foresee your spending and retirement lifestyle. The FIRE movement approaches this in two ways: Coast and Barista.
Coast FIRE enthusiasts usually save and invest much of their FIRE number decades before retirement. When they hit their FIRE number, they can "coast" through retirement because they have saved enough. But they choose to work at reduced hours to leave room to pursue their passions.
The term "barista" refers to having a low-stress, part-time job with flexible hours. Barista FIRE advocates typically set a lower retirement fund target for themselves, and instead choosing to work part-time jobs to supplement their income once they hit retirement.