F.I.R.E.

If you live on €24,000 a year, your FIRE number is around €600,000. The variable that accelerates the journey most is not returns: it is the savings rate. Someone saving 50% of income needs ~17 years from zero; someone saving 10%, more than 50. That is why the movement obsesses over saving as much as investing.

The movement's variants

• Lean FIRE: independence on minimal expenses (a permanently frugal lifestyle).
• Fat FIRE: the comfortable version — more wealth, no lifestyle cuts.
• Barista FIRE: wealth covering most expenses plus chosen part-time work.
• Coast FIRE: saving hard while young until compound interest alone guarantees a normal-age retirement; afterwards you only cover current expenses.

FIRE in Spain

The American framework needs translation: public healthcare removes the early retiree's biggest financial risk in the US version, while savings taxation (from 19%) affects every sale and dividend along the way. Social Security contributions and the future public pension add a cushion the pure 4%-rule maths ignores. Net effect: Spanish FIRE usually requires somewhat less portfolio than the American version for the same living standard.

Reasonable criticisms and risks

Sequence-of-returns risk (a major crash in the first retirement years), persistent inflation, unforeseen expenses over a 40-year horizon and the psychological factor — many people discover they want to work, just at something else — are serious objections. Veteran practitioners answer with flexibility: dynamic withdrawal rates, partial income and a safety margin in the target number.

Common mistakes

• Calculating the number with today's expenses without projecting tomorrow's (children, housing, care).
• Chasing extraordinary returns to shorten the timeline: the added risk can lengthen it instead.
• Treating the 4% rule as a law of physics rather than a US-based historical reference.