The amount of money you'll save on your mortgage if you make an extra mortgage payment each year will depend on the amount of the mortgage you took out and for how long the mortgage is for.
But lets take for example you took out a 30 year mortgage for $200,000.00 and the interest rate was 5% you would pay $186,512.00 in interest alone making the total mortgage cost $386,512.00
So if you made 1 extra mortgage payment per year you would get rid of the mortgage in 26 years vs 30 years and you would be saving $32,699.00 on the interest pay paying off the mortgage sooner.
So yes by all means if you can make that extra mortgage payment or two as the money saved doing so can really add up.