I paid extra towards my mortgage for a while!
In May 2007, I purchased a home with a 6.375% (30 year) mortgage rate. I didn't have 20% down, but I think I was able to pay something like $3k in extra closing costs to get a PMI-free mortgage.
In 2008, I made $1800 in extra payments.
In February 2009, I refinanced to 5% (15 year) with my credit union.
In 2010, I made $1500 in extra payments.
In October 2011, I refinanced again to a 3.375% (15 year) with my credit union.
In 2013, I made another $2500 in extra payments.
I started learning more about investing around this time. While I realized it would be cool to pay off my mortgage the rest of the way, it had already been reduced to about a 12 year mortgage, and the money could do me more good invested in a total stock market index fund. So I haven't paid any more extra on it. I researched refinancing this mortgage, but starting in 2014, this property was turned into a rental, and I didn't like my options as far as closing costs and interest rates, so I'm letting it ride.
In April 2016, my spouse and I purchased a home - we got a 3.75% 30 year fixed-rate mortgage. We didn't have enough to put down to avoid PMI. From May 2016 through September 2016, we paid just over $27,700 in additional payments towards the mortgage, and PMI was removed. We have not made any additional payments since then.