But is that grid system consistent across different sites? In my experience, I usually need to customize the "grid" to specific breakpoints and widths, as defined by designs/content. I find that it's often faster to just write a few helper classes for layout – specific to the site I'm working on – rather than use 15% of a framework's grid and still do heavy lifting. Of course, this isn't the case if the design team designs with a framework's grid system/breakpoints in mind.