I think part of the question is: If I pay off the mortgage, I can retire sooner since I'll need less money. If I don't pay off the mortgage, I'll have to work longer since I'll need the cash flow. Extra W-2 wages mean lots of extra taxes (plus SS and Medicare).
But I don't think that's the case. If you save/invest the extra mortgage money, then when you FIRE you'll have that much extra to pay off the mortgage. Right? Unless you plan on keeping the mortgage after FIRE, but it doesn't sound like that.
Denise, I saw your eye-popping salary on another thread this morning, and then immediately thought of all the taxes you have to pay, living in the Garden State. Ouch.
I also live in a HCOLA, but never had a salary that topped $100k. My average was somewhere in the $55-60k range, at best. I used to think this way (see: bolded above), so I completely understand. However, I had a very persistent boyfriend, who explained and explained why he only put 20% down (when he had lots more) and never, ever prepaid his mortgage. It took a long,
long time to sink in, because my mortgage payment was so huge compared to my income, but sink in it finally did.
It takes some time, but eventually your investments start to earn and grow. Then they start to earn more than you do. Along the way, as your investments grow, you will want to throw more at them instead of the mortgage. Eventually, the day comes when your investment balances are greater than your mortgage, at which point you know could pay it off in one payment, but the thrill of watching your investment accounts balloon far exceeds the thrill of prepaying a mortgage, especially as inflation continues to erode the real cost of that mortgage payment. Wow! What a paradigm shift!
In fact, the earlier you start saving and investing, the fewer actual dollars you will have to earn to fund your retirement. That's a total win. Also, knowing that you are a normal person, walking through life like anyone else, except for the fact that you have a million plus in invested assets, never stops being a thrill. Beats the hell out of prepaying a cheap-ass mortgage.
In conclusion: If you see a yet another post on this topic from me and wonder why the hell I keep on an' on about this topic, just tell my old BF JKS (wherever he is*) I'm just paying it forward.
*OMG, I just discovered that he lives one town over from me. Last I heard, he lived in Jakarta!