When you add responsive design into the equation, the process looks a bit different:
There’s a lot more planning and testing that needs to be done.
Since when a screen is resized, things need to move around, you have to plan which content takes priority over other content when the screen gets smaller:
You want your more important content to be at the top now. Other content blocks move down until you get to one column (for the smallest screen size).
Sometimes, you decide that some information does not show up… it disappears. This is probably more in extreme conditions where there’s a lot of content to show and you don’t want a page to scroll on too long – again, keeping the person viewing the website in mind (the user experience).