I totally agree with this. When I shifted my design thinking to use this approach to building UX, I found not only were my sites/apps easier to bring to mobile

I totally agree with this. When I shifted my design thinking to use this approach to building UX, I found not only were my sites/apps easier to bring to mobile but the desktop versions were usually better as well. Mobile first designs often lead to better designs on desktop, at least in my experience so far (with content-heavy apps).