Graduated from the 50-75k mortgage payoff club and joining this thread.
We took the original 90% mortgage for a 220k house back in 2010. Initial monthly payments were about 1,100, but we (I) aggressively re-mortgaged, plus the base rate kept plunging and the house appreciated in value after the "crash", and is now worth about 550k. Just the remortgaging left us with a nice chunk of leftover change, and we both had solid pay rises during the period (Mr Vashy's salary doubled and mine tripled). I had always overpaid a bit - sometimes I just wanted "round numbers", but with the excess cash sloshing around, we've made a bit more of an effort. Current monthly payments are sub-300.
At the November 2019 remortgage, we had just under 100k in principal outstanding, and we've now down to 50k. The goal is to kill the mortgage over the next two years. We can do 20k a year fairly comfortable, and I think we can stretch to 25k/year. We could do it faster but we also need to pad our cash savings (i.e. Vanguard S&S ISAs). We might also have to take on some debt again because we need a new roof and while we're at it, a loft conversion (would be a wise investment and also improve our quality of life, especially if we continue to work from home), because the house is very small.
Also, I have a freelancer side gig and have been eyeing the possibility to do that full time, but I'm not super comfortable with having a variable income while we still have debt, so the mortgage payoff day opens up a definite chance that I stop doing that 8-to-5 and do something else.