The final hurdle to clear before embarking on a responsive design is often one of mindset. And in some ways, this is perhaps the most difficult to overcome. For example, I'm often asked to convert existing graphic designs into standards compliant HTML/CSS and jQuery-based web pages. In my own experience, it's rare (and when I say rare, I mean it's never happened) for graphic designers to have anything other than a fixed-width "desktop version" of a site in mind when producing their design composites. My remit is then to create a pixel perfect rendition of that design in every known browser. Failing or succeeding in this task defines success in the eyes of my client, the graphic designer. This mindset is especially entrenched in clients with a background in printed media design. It's easy to understand their reasoning; a composite of the design can be signed-off by their own clients, they hand it to the frontend designer/developer (you or I), and we then spend our time ensuring the finished code looks as close as humanly possible to that design in all the major browsers. What the client sees is what the client gets.
However, if you've ever tried to get a modern web design looking the same in Internet Explorer 6 and 7 as it does in a modern standards compliant browser such as Safari, Firefox, or Chrome, you will understand the inherent difficulties. It's often taken me as much as 30 percent of a project's allocated time/budget to fix the inherent flaws and failings in these older ailing browsers. That time could have been spent building on enhancements and economizing code for the growing number of users viewing sites in modern browsers, rather than patching and hacking the code base to provide rounded corners, transparent images, correctly aligned form elements, and so on for a shrinking number of Internet Explorer users.
Unfortunately, the only antidote to this scenario is education. The client needs an explanation as to why a responsive design would be worthwhile, what it entails, and why the finished design won't and shouldn't look the same across all viewports and browsers. Some clients get there, some don't. Unfortunately, some still want all the rounded corners and drop shadows to look identical in Internet Explorer 6 too!
When I approach a new project, whether a responsive design is applicable or not, I try and explain the following points to my client:
By allowing older browsers to display the pages slightly differently, it means that code is more maintainable and cheaper to update in the future.
Making all elements look the same, even on older browsers (for example, Internet Explorer 8 and lower versions) adds a significant amount of images to a website. This makes it slower, more expensive to produce and more difficult to maintain.
Leaner code that modern browsers understand equates to a faster website. A faster website ranks higher in search engines than a slow one.
The number of users with older browsers is shrinking, the number of users with modern browsers is growing—let's support them!
Most importantly, by supporting modern browsers, you can enjoy a responsive web design that responds to the differing viewports of browsers on different devices.