Hey OT.

I think you should just back the mortgage out from your FIRE number but not pay it off.

So in 2023 you would payoff the mortgage plus have enough Stache to provide a 4%(?) SWR that would cover all expenses including the mortgage. Correct?

Then as an estimate/guess, in 2020 you would have $30K still due on the mortgage, and 3 years worth of $1,500/month payments totaling $45K (assuming interest, taxes, insurance, etc.). So run your numbers in 2020 and back that total mortgage payment out of your stache before calculating your SWR. Example: $1,200,000 - $45,000 = $1,155,000 * 4% = $46,200. If $46,200 fulfills your FIRE expenses you're ready.

Make sense?

You will be watching your stache disappear faster than 4% at first, but trust the math and retire when you're ready. It's ok to have debt when you retire. Here's to 2020. I hope to join you then.