If you haven't considered making your website(s) responsive, now is a great time to. Responsive websites are everywhere, and for good reason. Responsive design is, simply put, the best way to make your website look great on virtually any device.
In the past, if you wanted to create a website that looked great on desktop computers and smartphones, you needed to build two different versions of it. There would be one version that looked good on desktops and laptops, and other than looked good on some phones, but not all.
With responsive design, the page changes to fit your browser's window as it grows or shrinks. This ensures that your visitors receive the best possible experience for their particular browser.
Here is a great infographic made by Top 10 Website Hosting that offers additional insight.
Theming frameworks like Gantry 5 are built from the ground up to be responsive. You can choose your own breakpoints which tell the page which pieces of your page to display for a given screen size. So, for example, you can still have different elements of the page load for different types of devices, but this transition happens seamlessly.
Perhaps the most important reason to consider responsive design is that more of your visitors are using mobile devices than ever before. People around the world are using their phones to browse the web, check email, use social media, and even shop.