For everyone including me trying to talk numbers to one he doesn't understand doesn't care to understand and just trolls this shit he's done it a few times. As Ron white would say you can't fix stupid.

boarder42, thanks for giving me the impetus to join this forum.

So let's talk numbers. In general, I agree that most people most of the time should contribute to a taxable account of equities prior to paying down their mortgage (after of course maxing out as much traditional tax-deferred savings vessels as possible). However, there is clearly a time and a place for Mustachians to minimize the time to reach FI by choosing mortgage payments prior to additional assets going into a taxable account. (Note that minimizing time to FI is the goal, not maximizing expected assets.) Rather than spending a large amount of time going through the various scenarios and mathematical formulas, I'll provide a scenario where the choice should be clear even for the most determined dogmatists:

If the mortgage interest rate exceeds the SWR, and if the money is available to pay off the mortgage, and if after doing so one can reach FI, then the math unequivocally states that paying off the mortgage is the optimal scenario. Here's a hypothetical:

'Moe' has an asset allocation that gives him a presumed SWR of 4% (with 95% past success rate). He has a 30-yr $100k mortgage at 5% interest rate, with payments of $5k per year (simplification). He also has assets of $1M and current expenses of $45k per year. Moe's dear Aunt Sally passed away and left him $100k. How should Moe allocate his money to minimize the time to FI?

Note that the answer is completely independent of estimated equity returns. But if equity risk is taken into account, a prolonged market dip could add years to Moe's FI date.

All of this being said, here's where it makes most sense to invest rather than pay down a mortgage:

1) When you have tax-deferred space to fill.

2) When you have little to no liquid assets, leaving you open to liquidity risk.

3) Early in the FI journey, when all money has a long-term horizon where you can expect to receive historical market returns.

4) When mortgage interest rates are below historical market returns.

And here's where it makes most sense to pay off the mortgage rather than invest in a taxable account:

1) Late in your FI journey, when no mortgage payment would help achieve the desired SWR for FI in a short time period, thereby eliminating equity risk.

2) When mortgage interest rates are above historical market returns.

There are lots of scenarios that fall somewhere in the middle. At this point it comes down to risk tolerance, personal opinions, and expected outlook.

Bottom line, we should be strongly encouraging many people who have a long time horizon and a low-interest rate mortgage to be pumping money into a taxable account. But to act like this is the solution for everybody (or "99%") shows an immature understanding of risk and very basic math.