Bought and refi'd on the way down is what many people did. I was paying extra but at 2%, what's the point and why would I ever move unless I had to? 2014 - 5%

Bought and refi'd on the way down is what many people did. I was paying extra but at 2%, what's the point and why would I ever move unless I had to? 2014 - 5%/30y 2015 - 3.75%/30y 2016 - 2.75%/15y 2021 - 2%/10y