Five years is very admirable if you’re truly wealthy in FatFIRE, but may be too much in cash for most folks (~ $500k), and missing out on significant market growth. I’m struggling with this question now, and have settled on 2 - 3 years, not including the smallish (3-mo.) emergency fund and the fully-funded sinking funds for the next gently-used vehicle and new roof & HVAC down the road. I have significant funds in a brokerage 2035 target index mutual fund with a fairly large bond allocation in it that should otherwise weather a downturn pretty well, and this is the basic quarterly living expenses fund at present (2.5 - 3% SWR). We’ll see how it goes.