The thing I don't see in your plan above is your plan for health coverage. How do you plan to cover the next 20+ years of medical expenses for the four of you before the toddler/kids get their own policies, and/or you qualify for whatever government senior insurance that's in place when you hit 67?

I ask because many family policies through a group (like through work) with a $2k deductible run over $1000 a month, and private individual policies are much more expensive, even with larger $10K deductibles, and one child developing a chronic condition or a serious accident for any of you could wipe you out financially in a matter of weeks. $12000+ a year is a big hit for your proposed withdrawal rate.

Does your planned budget account for that kind of variable and possibly escalating cash layout?

Living in the U.S. with a number of chronic health conditions, one of which magically appeared in my 20s, has made me incredibly paranoid about just up and retiring before I have some kind of guaranteed minimum catastrophic health coverage that can't be cancelled out from under me, even if I had $3 million in cash.

-Heather