Specifically, running some spreadsheet projections it appears that our quickest route to FI would be to aggressively attack our mortgage, putting about $5K/mo. extra towards principle, and about $3K/mo. into post-tax index funds; while also maxing out 401k plans, HSA, and kids' 529 plans. This would have our mortgage paid off by February 2022, and I think this would have us FI a little over a year later, in May 2023 (when I'm 45), when our PPI (excluding home equity and kids' 529 plans) would be enough to cover our monthly expenses (given that our housing expenses would no longer include P/I for a mortgage). But by focusing most of our non-retirement/non-tax-advantaged savings on the mortgage as opposed to post-tax index funds, the projections would have our index fund account at about $550,000 in May 2023. Acknowledging that this would be more than sufficient for many of the people on this forum to live off indefinitely, our expenses (even when streamlined) are nowhere near ERE standards, given we have elementary school kids and we choose to put them in parochial school, among other things.
Assuming our monthly expenses at FI (i.e., when I'm 45 years old, and my wife is 44) are as follows:
- Housing: $960* (property tax, insurance, HOA, utilities)
- Kids: $2,577 (tuition, aftercare,** 529 contributions, random school/extra-curricular stuff)
- Everything else: $845 (phones, dog, food, consumables, car, clothing, entertainment, gifts, travel, internet)
- Total: $4,382
(*) Obviously, we have choices here. E.g., once our kids move from the school they are at to high school (in another part of town), we may choose to rent out our paid-off home and move into an apartment closer to the kids' high school. B/c our home is in a highly-sought-after public school district, I suspect we could get rent that would cover not only the $960 in housing expenses but also most of our own apartment rent, as the kids' high school is in a less desirous and therefore cheaper part of town--bringing our housing costs close to $0.
(**) Recognizing that we won't have to pay aftercare costs when the kids get older, I'm nevertheless continuing to factor in the number as I suspect that the aftercare money will get eaten up in kids' extra-curricular activities and other kids'-related stuff.