I still pay monthly but I started adding ten dollars a month to the payment the first year, 20 more the second year, 30 more the third year, 40 more the fourth year, 50 more the fifth year... I will have my 30 year mortgage paid off in 13 years.
The extra amount is large now, but we have the income to work it so we do.
Remember it is compounded so that extra 10 was just ten, then 20 was really 30 extra and the 30 became 60 and so on. For us it was totally painless and if we had an emergency we were not locked into anything but had flexibility.