If I ever had a mortgage, I would absolutely want to pay it off early - though, for me, the most likely scenario is that I will never have a mortgage to begin with.
I absolutely understand b42's maths - I have a maths degree, and I've read enough of the posts. I agree with him that in the case where the assumptions MMM and most Mustachians make about stock market performance are true, LongTermIncome(investing in stocks) > ReductionInExpenses(paying down mortgage). Personally, I think the assumptions may be somewhat optimistic, given that the twentieth century was effectively the golden age of oil, but I think stocks are unlikely to drop to zero, especially global. Stagflation's probably something to watch for, though. I'm definitely not as comfortable with putting 100% or even 80% into stocks, especially US stocks, at this point in time.
However, the fact that the mortgage payment IS an expense is not to be ignored, because it requires that you budget to pay it every single year, not just on the years where your investment income is doing well.
I think I am following a rather unconventional path to FIRE, which is what would make locking in such an expense very inconvenient for me. I'm self-employed, and effectively am planning to consider myself semi-retired by a varying amount until such time as I am fully FIRE. For me, a single, childless woman in my 20s, my priority is to keep my expenses as low as possible, because then it means I have fewer hours to work each year until I reach profit - and, because I'm trying to align at least some of my income sources with things I would do anyway, I'm unlikely to stop working once I reach that point each year, but once I do, it will take the mental pressure off because I know I won't be drawing down on my savings that year. Ideally, of course, I'd like to earn enough for at least a 50% savings rate, but the higher I can get it, the better. Right now, I have around £10000 between all the different places I have money.
I'm living with my parents at the moment, because this is a better option by far than either rent or mortgage: I'm effectively paying the amount I'd be paying for food only if I was by myself, and doing a bunch of chores, in exchange for food, shelter, and all bills included. This means that I expect my total expenditure to be less than £5000, even including car insurance, a (rare for me) foreign holiday, and about three different hobbies. Without the holiday and a couple of planned expensive hobby purchases, I could get it to less than £4000, I think. If I was having to pay bills, though, they would almost certainly be lower than average, because I try to be eco-friendly and therefore avoid turning lights on, turning the heating high, using tumble dryers, etc, whenever possible.
If I had a typical mortgage, monthly payments might cost £500 to £1000 per month, depending on the property - ie, I'd be spending more than my entire budget again just on a mortgage. This means I'd have to do at least twice as much work in a year to break even, and at least four times as much work in a year to get to a 50% savings rate.
Here is what I need to earn to achieve different savings rates:
| Savings Rate | Spend £4000 | Spend £5000 | Spend £10000 |
| 0% | £4000 | £5000 | £10000 |
| 10% | £4444.44 | £5555.55 | £11111.11 |
| 20% | £5000 | £6250 | £12500 |
| 30% | £5714.29 | £7142.86 | £14285.71 |
| 40% | £6666.67 | £8333.33 | £16666.67 |
| 50% | £8000 | £10000 | £20000 |
| 60% | £10000 | £12500 | £25000 |
| 70% | £13333.33 | £16666.67 | £33333.33 |
| 80% | £20000 | £25000 | £50000 |
| 90% | £40000 | £50000 | £100000 |
As you can see, by the time we make it to the 50-60% savings rates, the difference between expenses without locked-in mortgage or rent payments and with them are in the region of a whole extra full time minimum wage job per year. That's a whole bunch of extra success/hours of work I'd need with any given self-employed business endeavour, especially early on when my investments haven't had time to snowball yet.
That's why my home ownership plans are to continue living with my parents until either:
a) they die sudden unexpected early deaths and I inherit their house (and can either live there or downsize and buy a smaller house) (this is the most tragic option, so I'm hoping this isn't the option that happens)
b) I become successful enough with my self-employment/passive income endeavours that I can buy a decent house in a decent area outright with no mortgage and leave myself with a decent savings buffer, and then, if I don't have a romantic partner by then, immediately invite one or more of my friends (I have a few who are also single and living in their parents' houses) to come live with me in exchange for an even share of all the bills
c) my parents kick me out for some reason (not likely since we have a good relationship and I actually do stuff that is useful around the house) and I get a temporary rental place, and then try and move in with a different friend or relative, offering to pay an even share of food and bills and do a bunch of chores in exchange.
I think the argument is that the interest I got from the investments would cover the difference in expenses. But the stock market goes up and down, and I'm not as confident in it as some. Maybe I just have a low risk tolerance. It won't cover the expenses difference every year.
