Earlier quoted context omitted.
>> ... Bump it to 35% and you'll retire after 25 years. Bump it to 50% and retire in 17. Bump it to two-thirds and retire in 10 years. Can you/someone please point to the maths behind this? It sounds to me there are some assumptions about returns on investments and inflation rates.
The math is covered here: http://earlyretirementextreme.com/ Basically the thought is that 20-25 years of living expenses will generate enough income for you to early retire on. If you make 100k (post tax) with a 20% savings rate, you save 20k, and have living expenses of 80k. Ignoring future compound growth, for each year you work, you save 1/4 a year of living expenses. If you go the other extreme, and have 66% sav…
Ignoring growth rates and inflation is also a huge simplification. E.g. 3% yearly growth doubles your money in about 24 years. So it may again be a factor bigger than two between the two scenarios above.