The 4% withdrawal rate has been challenged, and one shouldn't use it as a guaranteed safe rate. It included massive bull runs that may not be repeated going forward. A lot of research has predicted lower real rates of return (around 4% average) in the next date.

> one shouldn't use it as a guaranteed safe rate

of course not - there are no certainties

> It included massive bull runs that may not be repeated

it also worked through times like the great depression; on aggregate it's amazingly resilient

> A lot of research has predicted lower real rates of return

This is a SUPER-important thing for making your own FI models!

It is based off of the best available information.

Don't forget to include the percentage required to offset inflation.

EDIT: Missed that this was for a fixed period of time - 30 years.

But... what happens if you live more than 30 years past your retirement? It would really suck to retire on $750,000 (or $1M) savings at 45, and live to be 100.

Included in the rate I quoted, per the trinity study, although you might need to reduce your withdrawal rate below that some years depending on your asset holdings (see below for detailed info).

EDIT: Again, the rate quoted is for withdrawals in perpetuity. It doesn't guarantee your savings will outlive you, but it's highly confident it will.

https://www.bogleheads.org/wiki/Trinity_study_update

Some research suggests that a 3.5% withdrawal rate will last basically forever.

See, e.g. https://www.kitces.com/blog/adjusting-safe-withdrawal-rates-...

I know it's not what most people want, but if you retired to a country with a low cost of living that $1M would be more than enough to live really comfortable till you die.