Personally, I would say yes!.
Let’s start by explaining some things.
Back in the day we accessed the internet via a desktop computer, or maybe a laptop, screen sizes and computer speeds were pretty low, slow and inconsistent. But at least we knew roughly a few things about our potential visitors.
They would probably be viewing our sites either at 800×600 or 1024×768 (and there are some here who actually remember 640×480!), or as screen sizes increased and TFTs became common place, most users began to view our sites using 1280×1024 screens, this was fine. I could design my site to fit.
Now, things have moved on, once a mobile site would and could only be simple text, maybe a little colour and a couple of tiny pixelated images. Now mobile is here, tablets, netbooks and other strange net connected devices are cropping up. So where does that put me when designing a new site?
Now we have to cater for a whole range of devices. Previously there was no choice in the matter, M.website.com or www.website.com. One pretty basic site and another rigid one.
We’re talking websites here, so if you’re wondering about when to make a mobile site or app, you’ll have to come back for that.
This is where Responsive Web Design comes in. Instead of developing a website specifically for one screen size, we can now detect the browser/device/tablet/phones viewable space, and adapt the design to fit.
Take a look at our new site built in this manner.
On my beloved 27″ iMac, instead of seeing a postage stamp, I see it in its full glory, then on my mobile I get the full experience, just nicely folded down.
Same site, same code. But with a little thinking it scales up and down gracefully.