With everything you should try to stay within the trends, at least every two or so years. The past couple of years mobile design or something you’ve heard called “mobile responsive” has been on the radar with Google in relation to SEO & website validation. In reguards to design it’s always best to keep your brand as similar as possible, even if or when you are developing applications. That’s why, I try to always impress the importance of mobile responsive design to our clients.