For the uninitiated, this calculator is actually for a broader movement called FIRE (Financial Independence Retire Early). They have subreddits at r/financialindependence and r/fire, and variants for the more ambitious like FatFIRE.
The general FIRE modus operandi is to live very financially frugally for a period of time (several years or more) to save as much money as possible to, well, retire early (or at least be comfortable with a less intensive and lower paying job).
> The general FIRE modus operandi is to live very financially frugally for a period of time (several years or more) to save as much money as possible to, well, retire early (or at least be comfortable with a less intensive and lower paying job).
This is a subset. The only real mechanism/requirement is saving enough to retire or be financially independent, over whatever timeframe you want. That means typically means 20-30% or higher savings rate on income. One way to increase your savings rate is to have low expenses -- live frugally, as you say. The other way is to have high income.
The general FIRE modus operandi is to live very financially frugally for a period of time (several years or more) to save as much money as possible to, well, retire early (or at least be comfortable with a less intensive and lower paying job).