"I'd argue that it's more correct to describe a class once and apply it to many elements (OOCSS) than it is to describe it many times over and apply it to each

"I'd argue that it's more correct to describe a class once and apply it to many elements (OOCSS) than it is to describe it many times over and apply it to each element individually (Sass @extend)." What makes you say that the Sass approach is describing it "many times over"? It's described in one place: the %placeholder declaration. There are three steps in the process: + Describe the pattern. + Apply the pattern to components. + Apply the components to elements. In OOCSS, you: + Describe the pattern once. + Apply the pattern n times per component. + Apply the component n times per element. In OOSass, you: + Describe the pattern once. + Apply the pattern once per component. + Apply the component n times per element. The OOSass is much DRYer because if you've decided already that all .dropdown-menu-item's are going to be `.media` patterns, you do that once. You don't have to keep repeating that decision every time you write a new dropdown.