The other thing they don't mention is that even if you buy a new house or do a full renovation, all the big things like kitchen and bathroom renovations and replacing decks, roofs etc - they all need doing about the time you want to retire. So just planning to pay off your house before then is not enough, you need to plan to also have enough to do some major work on it.

The timing is something that worked fine when you could buy a house by 30 and take 20 years to pay it off, you had plenty of time to then pay for extra work on the house etc. after the mortgage was paid, but when you push back the age you can purchase and extend the loan period it makes it a lot more difficult.